Is the obstetric outcome of in vitro fertilized singleton gestations different from natural ones? A controlled study

Objective: To determine whether singleton IVF pregnancies carry adverse maternal or fetal outcome when compared with naturally conceived gestations.

Design: An analysis of the obstetric outcome of singleton IVF pregnancies in comparison with matched, naturally conceived singleton controls. Setting: In vitro fertilization unit and obstetric service at a tertiary medical center.

Patient(s): Two hundred sixty consecutive singleton IVF pregnancies and 260 naturally conceived singleton controls matched 1:1 for maternal age, parity, ethnic origin, and location and date of delivery.

Intervention(s): In vitro fertilization-ET.

Main Outcome Measure(s): The rate of antenatal obstetric complications, nonvertex presentation, cesarean section, preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality.

Result(s): The rates of most antenatal complications were similar in both groups. Urinary tract infection was the only complication diagnosed significantly more frequently after IVF (7.3% versus 1.2%); however, the rates of severe urinary tract infection necessitating hospitalization were similar. The incidence of nonvertex presentation was also similar. The cesarean section rate was significantly higher among IVF patients (41.9% versus 15.5%). The rates of preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality were comparable.

Conclusion(s): When controlling for maternal age, parity, ethnic origin, and location and date of delivery, singleton IVF pregnancies do not carry an increased risk for prematurity, low birth weight, or maternal or fetal complications. Still, these pregnancies are associated with a high rate of cesarean sections.     

Perinatal outcome of ICSI pregnancies compared with a matched group of natural conception pregnancies in Flanders (Belgium): a cohort study

A retrospective cohort study was conducted with an intracytoplasmic sperm injection (ICSI) group and a naturally conceived comparison group. A total of 1655 singleton and 1102 twin ICSI births were studied with regard to perinatal outcome. Control subjects (naturally conceived pregnancies) were selected from a regional registry and were matched for maternal age, parity, place of delivery, year of birth and fetal sex. The main outcome measures were duration of pregnancy, birth weight, Apgar score <5 after 5 min, neonatal complications, perinatal death and congenital malformations. Twin births, when compared with singletons, carry a much higher risk of poor perinatal outcome. For both ICSI singletons and ICSI twins, no significant difference was found between ICSI and naturally conceived pregnancies for all investigated parameters. After excluding like-sex twin pairs, ICSI twin pregnancies were at increased risk for perinatal mortality (OR = 2.74, CI = 1.26-5.98), prematurity (OR = 1.38, CI = 1.10-1.75) and low birth weight (OR = 1.34, CI = 1.06-1.69) compared with spontaneously conceived different-sex twin pairs. In conclusion, the perinatal outcome of ICSI singleton and twin pregnancies was very similar to that of spontaneously conceived pregnancies in this large cohort study. After excluding like-sex twin pairs, ICSI twins were at increased risk for prematurity, low birth weight and higher perinatal mortality compared with the natural conception comparison group.     

IVF twins have similar obstetric and neonatal outcome as spontaneously conceived twins: a prospective follow-up study

Studies comparing the outcome of spontaneous versus IVF twin pregnancies report heterogeneous results. This may depend on differences in the studied populations and/or in the management approach to twin pregnancy. The aim of the present study was to compare both maternal and perinatal outcomes in dichorionic diamniotic twin pregnancies who where spontaneously conceived or originated by successful homologous IVF. In order to get homogeneous observations, monochorionic twin pregnancies and triplet pregnancies were excluded. Moreover, to avoid any possible bias deriving from differences in the obstetric management, all pregnancies were managed by the same team applying fixed obstetric protocols. The study included 223 twin pregnancies, 84 conceived by IVF and 139 spontaneously conceived. Overall, maternal and perinatal outcomes were similar in the two groups: no significant differences were observed as far as gestational age at delivery, birthweight, perinatal morbidity and mortality, and rate of malformations were concerned. The rate of Caesarean section was slightly, but not significantly, higher in IVF pregnancies. In conclusion, the outcome of IVF twin pregnancies is comparable to that of spontaneously conceived twin pregnancies, provided that the same management criteria are applied.     

Perinatal outcome of pregnancies after assisted reproduction: a case-control study.

OBJECTIVE: We conducted a case-control study of all pregnancies obtained with assisted reproduction technology in the Dutch-speaking part of Belgium from 1992 until 1997 to investigate differences in peripartum obstetric events and the perinatal outcome. STUDY DESIGN: Three thousand fifty-seven singleton and 1241 twin pregnancies were studied. About 90% of pregnancies resulted from in vitro fertilization; the remainder resulted from intracytoplasmic sperm injection. Control subjects were selected from a regional register and were matched for maternal age, parity, fetal sex, plurality, and date of delivery. The main outcome measures were duration of gestation, birth weight, perinatal death, perinatal morbidity, incidence of congenital malformations, and incidence of cesarean delivery. RESULTS: Odds ratios and 95% confidence intervals were 2.6 (1.4-4.8) for perinatal mortality, 3.5 (2.2-5.7) for birth before 33 weeks of gestation, and 1.7 (1.5-1.9) for cesarean delivery in singleton pregnancies that resulted after in vitro fertilization. Twin pregnancies obtained with in vitro fertilization, on the contrary, were similar for all outcome measures, except for the incidence of cesarean delivery (odds ratio, 1.4; 95% confidence interval, 1.2-1.7) compared with spontaneously conceived twin pregnancies. CONCLUSION: The perinatal outcome of singleton pregnancies obtained with in vitro fertilization is significantly worse than that of spontaneously conceived pregnancies, mainly because of the increased rate of preterm birth. The outcome of twin pregnancies obtained with in vitro fertilization is comparable with that of normally conceived twins. For both singleton and twin pregnancies obtained with in vitro fertilization, the incidence of cesarean delivery is increased.     

Maternal risks and perinatal outcome in a Danish national cohort of 1005 twin pregnancies: the role of in vitro fertilization

BACKGROUND: Twin pregnancies constitute 25% of all in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) pregnancies. There is a lack of knowledge on maternal risks and perinatal outcome of IVF/ICSI twin pregnancies. METHODS: National survey by questionnaire (n = 1769). The study population consisted of all IVF/ICSI twin mothers (n = 266) and the two control groups of all IVF/ICSI singleton mothers (n = 764) and non-IVF/ICSI twin mothers (n = 739) who delivered in Denmark in 1997. The response rate was 89% among IVF twin mothers and overall 81%. RESULTS: In terms of maternal risks and perinatal outcome no significant differences were observed between IVF/ICSI twin and non-IVF/ICSI twin pregnancies after stratification for maternal age and parity. Nevertheless, IVF/ICSI twin mothers were more frequently on sick leave (OR 2.5, 95% CI 1.5-4.0) and hospitalized (OR 1.9, 95% CI 1.3-2.8) during pregnancy. Compared with IVF/ICSI singleton pregnancies, IVF/ICSI twin pregnancies were characterized by a higher incidence of preeclampsia (OR 2.4, 95% CI 1.5-4.2) and a higher frequency of sick leave (OR 6.8, 95% CI 4.4-10.5) and hospitalizations during pregnancy (OR 3.5, (95% CI 2.5-4.9); moreover, mean birthweight (p < 0.001) and gestational age (p < 0.001) were lower. No differences were observed in the incidence of pregnancy-induced hypertension and gestational diabetes between IVF/ICSI twin and singleton pregnancies. CONCLUSION: Although this population study indicates that maternal risks in IVF/ICSI twin pregnancies are comparable with non-IVF/ICSI twin pregnancies, the IVF/ICSI twin mothers were more likely to be on sick leave or hospitalized during pregnancy. Furthermore, maternal risks were higher and obstetric outcome poorer in IVF/ICSI twin vs. IVF/ICSI singleton pregnancies.     

Perinatal Outcome of Pregnancies After Assisted Reproduction: A Case–Control Study

Purpose: A matched case–control study of all pregnancies obtained after either IVF or ICSI was conducted to investigate the perinatal outcome. Methods: Three hundred eleven singleton and 115 twin pregnancies obtained after assisted reproduction were studied. Controls were selected from a regional register and were matched for maternal age, parity, singleton or twin pregnancy, and date of delivery. Results: No significant difference was observed for gestational age at delivery, birth weight, incidence of congenital anomalies, and incidence of perinatal mortality between ART (singleton and twin) pregnancies and spontaneous controls. ART twin pregnancies showed a higher incidence of preterm deliveries than control pregnancies (52 vs 42%; P < 0.05) and needed more neonatal intensive care (47 vs 26%; P < 0.05). Conclusions: From this case–control study it is concluded that the perinatal outcome of ART singleton pregnancies is not different from that in matched controls. ART twin pregnancies showed a higher incidence of preterm deliveries than control pregnancies and needed more neonatal intensive care.     

Perinatal outcomes in singletons following in vitro fertilization: a meta-analysis

OBJECTIVE: To estimate whether singleton pregnancies following in vitro fertilization (IVF) are at higher risk of perinatal mortality, preterm delivery, small for gestational age, and low or very low birth weight compared with spontaneous conceptions in studies that adjusted for age and parity. DATA SOURCES: We searched MEDLINE, BIOSIS, Doctoral Dissertations On-Line, bibliographies, and conference proceedings for studies from 1978-2002 using the terms "in vitro fertilization," "female infertility therapy," and "reproductive techniques" combined with "fetal death," "mortality," "fetal growth restriction," "small for gestational age," "birth weight," "premature labor," "pre-term delivery," "infant," "obstetric," "perinatal," and "neonatal." METHODS OF STUDY SELECTION: Inclusion criteria were singleton pregnancies following IVF compared with spontaneous conceptions, control for maternal age and parity; 1 of the above outcomes; and risk ratios or data to determine them. Study selection and data abstraction were performed in duplicate after removing identifying information. TABULATION, INTEGRATION, AND RESULTS: Fifteen studies comprising 12,283 IVF and 1.9 million spontaneously conceived singletons were identified. Random-effects meta-analysis was performed. Compared with spontaneous conceptions, IVF singleton pregnancies were associated with significantly higher odds of each of the perinatal outcomes examined: perinatal mortality (odds ratio [OR] 2.2; 95% confidence interval [CI] 1.6, 3.0), preterm delivery (OR 2.0; 95% CI 1.7, 2.2), low birth weight (OR 1.8; 95% CI 1.4, 2.2), very low birth weight (OR 2.7; 95% CI 2.3, 3.1), and small for gestational age (OR 1.6; 95% CI 1.3, 2.0). Statistical heterogeneity was noted only for preterm delivery and low birth weight. Sensitivity analyses revealed no significant changes in results. Early preterm delivery, spontaneous preterm delivery, placenta previa, gestational diabetes, preeclampsia, and neonatal intensive care admission were also significantly more prevalent in the IVF group. CONCLUSION: In vitro fertilization patients should be advised of the increased risk for adverse perinatal outcomes. Obstetricians should not only manage these pregnancies as high risk but also avoid iatrogenic harm caused by elective preterm labor induction or cesarean.     

Compartment syndrome after gynecologic laparoscopy: systematic review of the literature and establishment of normal values for postoperative serum creatine kinase and myoglobin levels

Purpose

The worldwide prevalence of adverse pregnancy outcomes (APOs) in singleton pregnancies after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) is suggested to vary; however, a complete overview is missing. The aim of this review is to estimate the worldwide prevalence of APOs associated with IVF/ICSI singleton pregnancies.

Methods

PubMed, Google Scholar, Cochrane Libraries, and Chinese databases were searched for studies assessing APOs among IVF/ICSI singleton births through March 2016. The prevalence estimates were summarized and analyzed by meta-analysis.

Results

Fifty-two cohort studies, with 181,741 IVF/ICSI singleton births and 4,636,508 spontaneously conceived singleton births, were selected for analysis. Among IVF/ICSI singleton pregnancies, pooled estimates were 10.9% [95% confidence interval (CI) 10.0–11.8] for preterm birth, 2.4% (95% CI 1.9–3.0) for very preterm birth, 8.7% (95% CI 7.4–10.2) for low birth weight, 2.0% (95% CI 1.5–2.6) for very low birth weight, 7.1% (95% CI 5.5–9.2) for small for gestational age, 1.1% (95% CI 0.9–1.3) for perinatal mortality, and 5.7% (95% CI 4.7–6.9) for congenital malformations. The IVF/ICSI singleton pregnancies have higher prevalence of APOs compared with those conceived naturally (all P = 0.000). Significant differences in different continents, countries, income groups, and type of assisted conception were found.

Conclusions

The IVF/ICSI singleton pregnancies are at a higher prevalence of adverse perinatal outcomes compared with those conceived naturally. Important geographical differences were found. Yet, population-wide prospective APO registries covering the entire world population for IVF/ICSI pregnancies are needed to determine the exact perinatal prevalence.

     

Perinatal outcome of twin pregnancies after in vitro fertilization

BACKGROUND: There are conflicting data concerning perinatal outcome of twin, in vitro fertilization (IVF) pregnancies. The aim of this study was to evaluate and compare perinatal and neonatal outcomes in twin IVF pregnancies to those of spontaneously conceived twin gestations. METHODS: The medical files of 73 IVF and 148 naturally conceived twin pregnancies were studied retrospectively. Data concerning maternal characteristics, obstetric complications, and neonatal outcome were recorded and compared by chi2 test. The one-way analysis of variance (anova) was used to compare the means of groups. RESULTS: Mean maternal age, the proportion of nulliparous women, and the incidence of premature rupture of membranes, cesarean section, and premature delivery were significantly higher in the study group. The mean birthweight was significantly lower, the frequency of admission to the intensive care unit and the duration of hospitalization were significantly higher in the study group. The incidence of intraventricular hemorrhage was significantly higher in the IVF group. The number of perinatal deaths was similar. CONCLUSION: IVF twin pregnancies are at greater risk for obstetric complications and adverse neonatal outcome in comparison with naturally conceived twin gestations.     

Screening for Down syndrome in dichorionic twin pregnancies conceived by in vitro fertilization (IVF): a clinical pilot study to confirm the laboratory methods

Purpose

The corrections necessary to estimate the risk for Down syndrome in twin pregnancies have been pointed out. We performed a nested controlled study to evaluate the validity of these corrections in dichorionic twins conceived by IVF.

Methods

Detailed clinical data was collected from the medical records. Twins were matched with a contemporaneous cohort of spontaneously conceived singleton pregnancies that serve as reference in a 1 to 4 ratio. All patients had their entire obstetrical care at our Hospital. The Student t-test was used for group comparisons and a p-value <0.05 was considered significant.

Results

Nineteen sets of normal twins concordant in size and with appropriate weight for gestational age were matched with 80 normal and mature newborns. Significant differences between groups were found for maternal age, gestational age at delivery and newborn weight (all p < 0.01). No statistical differences were noted for the levels of the biochemical markers expressed as multiples of the median. However, a 15 % closer approximation to the laboratory median for PAPP-A and a 10 % closer approximation to the laboratory median for free β-hCG was evident in twins when compared to the reference group.

Conclusions

These findings support the methods used to estimate the risk for Down syndrome in dichorionic twin pregnancies conceived after IVF. A future study with a larger sample size could confirm if the laboratory corrections done on the combined screening test improve the predictability of Down syndrome in dichorionic twin pregnancy conceived by IVF when compared to singleton pregnancies.     

Preeclampsia acts differently in in vitro fertilization versus spontaneous twins

Objective

To investigate risk factors and pregnancy outcome of spontaneous vs in-vitro fertilization (IVF) twins complicated with preeclampsia.

Study design

A retrospective population-based cohort study comparing maternal and neonatal outcome in IVF vs spontaneously conceived twins was conducted. Deliveries occurred in a tertiary medical center between the years 1988 and 2010. Women who conceived after ovulation induction and those with chronic hypertension were excluded from the study. Multiple logistic regression models were used to control for confounders.

Results

The study population included 4428 twin pregnancies, of these 314 (7.1%) had preeclampsia; 64 (20.3%) were IVF twins and 250 (79.7%) were spontaneous twins. Preeclampsia was more common in IVF compare to spontaneous twins (13.8 vs 7.6%, OR = 1.81, CI = 1.50–2.17, P < 0.001). The mothers of IVF twins were significantly older, and were more likely to be nulliparous. The rate of cesarean delivery was higher among IVF twins. The mean gestational age at delivery and the mean birth weight were significantly lower in IVF twins. While controlling for confounders using a multivariate analysis, IVF was found as an independent risk factor for preterm delivery in twin pregnancies with preeclampsia. However, there was no difference in the perinatal mortality or 5 min Apgar scores < 7 between the two groups.

Conclusion

Preeclampsia is more common in IVF twins compared to spontaneous twin pregnancies. IVF twins with preeclampsia are at an increased risk for cesarean delivery, preterm delivery and low birth weight.

     

Obstetric outcome of twin pregnancies conceived by in vitro fertilization and ovulation induction compared with those conceived spontaneously

OBJECTIVE: To compare the obstetric characteristics of twin pregnancies conceived by in vitro fertilization (IVF) and ovulation induction with those conceived spontaneously. DESIGN: Case control study. SETTING: Tertiary Medical Center. PATIENTS: All twin deliveries that were achieved by IVF (n=558) and ovulation induction (n=478) from January 1988 through December 2002 were evaluated. Each group was compared with a control group that conceived spontaneously (n=3694) and was delivered during the same period. INTERVENTIONS: Ovulation induction, IVF-ET. MAIN OUTCOME MEASURES: Obstetrical complications. RESULTS: Multivariate analysis showed that patients who conceived with the assistance of IVF and ovulation induction had a significantly higher risk for gestational diabetes mellitus (odds ratio [OR]=2.41, 95% confidence interval [CI]=1.77-3.29 and OR=1.71, CI=1.2-2.42, respectively), cesarean section (OR=2.17, 95% CI=1.74-2.70 and OR=1.76, CI=1.43-2.16, respectively), and a lower gestational age at birth in the IVF group (OR=0.91, 95% CI=0.88-0.94), compared with their controls. CONCLUSIONS: After controlling for maternal age, and nulliparity we demonstrated that twin pregnancies conceived with the assistance of IVF and ovulation induction are at increased risk for gestational diabetes mellitus, and delivery by cesarean section. In addition, IVF conceived pregnancies have a lower gestational age at birth.     

Obstetric and perinatal outcome of 1655 ICSI and 3974 IVF singleton and 1102 ICSI and 2901 IVF twin births: a comparative analysis

A total of 3974 IVF and 1655 ICSI singleton births and 2901 IVF and 1102 ICSI twin births were evaluated. Pregnancies after both fresh and frozen transfers were included. IVF and ICSI singleton pregnancies were very similar for most obstetric and perinatal variables. The only significant difference was a higher risk for prematurity (< 37 weeks of amenorrhoea) in IVF pregnancies compared with ICSI pregnancies (12.4 versus 9.2%, OR = 1.39, 95% CI = 1.15-1.70). For twin pregnancies, differences were not statistically different except for a higher incidence of stillbirths in the ICSI group (2.08 versus 1.03%, OR = 2.04, 95% CI = 1.14-3.64). Intrauterine growth retardation with or without pregnancy-induced hypertension was observed more often in the ICSI group. Regression analysis of the data with correction for parity and female age showed similar results for twins. For singletons, this analysis showed similar results with the exception of low birth weight babies (< 2500 g), which were also observed more often in IVF pregnancies (9.6 versus 7.9%, OR = 0.79, CI = 0.65-0.98, P = 0.03). This large case-comparative retrospective analysis showed that the obstetric outcome and perinatal health of IVF and ICSI pregnancies is comparable.     

The vanishing twin: Diagnosis and implications

Vanishing twin syndrome (VTS), defined by first-trimester spontaneous loss of a twin, is a common phenomenon with a reported prevalence of 15–35% of twin pregnancies. The etiology of VTS is obscure. Still, several risk factors have been identified, including an increased number of embryos transferred in pregnancies conceived by in vitro fertilization, an initial increased number of gestational sacs and advanced maternal age.The effect of VTS on obstetric and perinatal outcomes is controversial. Several studies have reported that pregnancies with VTS were associated with increased risk for preterm birth and small for gestational age neonates compared to singleton pregnancies, while others showed no difference in perinatal outcomes.The prevalence of placental vascular and anatomic abnormalities such as small placentas was higher in VTS. These findings lay an essential foundation for understanding how this phenomenon affects obstetric and perinatal outcomes of the surviving pregnancy.     

Obstetric and neonatal risk of pregnancies after assisted reproductive technology: a matched control study

BACKGROUND: The aim of the study was to evaluate the obstetric and neonatal outcome of pregnancies after assisted reproduction technology (ART) in comparison with matched controls from spontaneous pregnancies. METHODS: A total of 12 920 deliveries at the Department of Obstetrics and Gynecology, University of Szeged, from 1 January 1995 to 31 December 2001 were subjected to retrospective analysis. Two hundred and eighty-four singleton, 75 twin and 17 triplet pregnancies after ovulation induction (n = 114; 30.3%), intrauterine insemination (n = 33; 8.8%) and in vitro fertilization (n = 229; 60.9%) were evaluated. The pregnancy outcome of the singleton and twin pregnancies was compared with that for controls matched with regard to age, gravidity and parity and previous obstetric outcome after spontaneous pregnancies. RESULTS: Twenty-four percent of the assisted reproductive pregnancies were multiple pregnancies. The incidences of singleton intrauterine growth retardation (IUGR) and preterm birth were reasonably similar to those among the controls (IUGR: 6.3% vs. 4.2%; preterm births: 13.0% vs. 9.9%, for the cases and the controls, respectively). As compared with the controls, there was an increased incidence of cesarean section among the singleton (41.2% vs. 34.5%, p = 0.12; OR 1.33; 95% CI 0.95-1.87) and twin assisted reproduction pregnancies (66.7% vs. 60.0%), but without significant differences. CONCLUSIONS: Increased obstetric risk could be observed concerning threatened preterm delivery and cesarean section rate in the study group. The perinatal outcome of singleton and twin pregnancies following assisted reproductive techniques is comparable with that of spontaneously conceived, matched pregnancies.     

Analysis of 104 twin pregnancies conceived with assisted reproductive technologies and 193 spontaneously conceived twin pregnancies

OBJECTIVE: To evaluate pregnancy outcome of assisted reproductive technology (ART)-conceived twin pregnancies. DESIGN: Retrospective study. SETTING: A tertiary obstetric care center. PATIENT(S): All twin pregnancies delivered > or = 24 weeks of gestation from January 1, 1996, to December 31, 1997. INTERVENTION(S): Maternal and neonatal record review. MAIN OUTCOME MEASURE(S): Pregnancy and perinatal outcome. RESULT(S): The study group comprised 104 ART-conceived twin pregnancies, and 193 non-ART-conceived pregnancies served as controls. Mean maternal age, the proportion of nulliparae, and the percentage of women who delivered before 34 weeks' gestation was higher among the study women, whereas mean gestational age was younger. The incidences of pregnancy-induced hypertension, uterine bleeding, premature contractions, intrauterine growth retardation, fetal death, discordance, and cesarean section were significantly higher in the study group. Correspondingly, in the study group, the mean birth weight of both twins was lower; more neonates weighed < 1, 500 g, more had Apgar scores of < 7 at 5 minutes, more were admitted to the intensive care unit, and more second twin neonates died. The outcome of twin pregnancies conceived spontaneously was comparable with those conceived by ovulation induction. CONCLUSION(S): Assisted reproductive technology-conceived twin pregnancies are at greater risk than non-ART-conceived ones for pregnancy complications and adverse perinatal outcome.     

Obstetric outcomes of elderly primiparous singleton pregnancies conceived by <Emphasis Type="Italic">in vitro</Emphasis> fertilization compared with those conceived spontaneously

Aim:  To examine the obstetric outcomes of elderly primiparous singleton pregnancies conceived by in vitro fertilization (IVF) compared with those conceived spontaneously.
Methods:  Data were collected from primiparous women aged 35 years and older with a singleton pregnancy conceived by IVF ( n  = 89) or spontaneously ( n  = 849). Data included antenatal data, gestational age at delivery, obstetric complications, such as pregnancy-induced hypertension, gestational diabetes, placental previa and placental abruption, mode of delivery, birth weight, fetal demise and the Apgar score at 1 min.
Results:  The elective Cesarean rate in pregnancies following IVF was significantly higher than that in the control group ( P =  0.014). However, there were no significant differences in obstetric outcomes between the two groups.
Conclusions:  The current results did not support the IVF-related risks of elderly primiparous singleton pregnancies. (Reprod Med Biol 2007; 6: 219–222)     

Clomiphene Citrate and Pregnancy Outcome

Summary: Data from Australia and elsewhere have shown consistently that adverse perinatal outcomes such as preterm birth and perinatal mortality are more common in pregnancies resulting from assisted conception with IVF and GIFT than normally conceived pregnancies. Factors that may contribute to the excess of poor outcomes include maternal factors, the assisted conception procedures themselves and possibly the influence of drugs used to induce superovulation. This review examines the medical literature describing pregnancies following ovulation induction with one of the drugs used to induce superovulation, clomiphene citrate, and compares their outcomes with Australian IVF and GIFT pregnancy outcomes.
The review shows that whilst some studies have suggested higher rates of ectopic pregnancy, spontaneous abortion and congenital malformations in clomiphene citrate induced pregnancies, the findings are inconsistent and the data are flawed. There are only very poor data available on the incidence of preterm birth. Multiple pregnancy is a well-recognized adverse outcome of clomiphene citrate induced pregnancies. Attempts to improve perinatal outcomes of pregnancies following assisted conception will be helped by a better understanding of the relative contributions of maternal and treatment factors and further studies of pregnancy outcome after ovulation induction are needed.     

Increased risk of preterm birth in singleton pregnancies resulting from in vitro fertilization-embryo transfer or gamete intrafallopian transfer: a meta-analysis

OBJECTIVE: To perform a systematic review of the literature to determine whether singleton pregnancies resulting from IVF-ET/GIFT are at higher risk for preterm birth (<37 weeks). DESIGN: Literature search and systematic review. SETTING: Medical school. INTERVENTION(S): A MEDLINE search (1965-2000) was performed using the terms "premature labor," "infertility," "pregnancy complications," "gonadotropins," "pregnancy outcome," "preterm delivery," and "in vitro fertilization." Criteria for inclusion were English language, original research article, study patients conceived using IVF-ET (with or without intracytoplasmic sperm injection) or GIFT, pregnancy outcome reported compared with a control group (e.g., naturally conceived singletons at their hospital or a national reference), and prematurity clearly defined. Incomplete articles (e.g., abstracts), reports of other studies, and studies that failed to separate multiple from singleton gestations were excluded. MAIN OUTCOME MEASURE(S): Summary of relative risks of preterm birth. RESULT(S): Twenty-seven articles met all inclusion/exclusion criteria and were analyzed by meta-analysis. The random-effects summary relative risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT was 1.98 (95% confidence interval, 1.77-2.22). CONCLUSION(S): The risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT is twice that of natural conceived pregnancies.     

Pronóstico perinatal y materno de las gestaciones gemelares concebidas mediante fecundación in vitro,en relación con las obtenidas espontáneamente

Objective

To determine the outcomes of twin pregnancies resulting from in vitro fertilization (IVF) compared with those resulting from spontaneous conception.

Material and methods

We performed a historical cohort study comparing neonatal outcomes of twin pregnancies resulting from IVF (n = 44) with those resulting from spontaneous conception (n = 109) in the Complejo Hospitalario Universitario de Albacete (Spain) in 2001, 2001 and 2003. The primary variable was perinatal mortality. Secondary variables were fetal morbidity (neonatal abnormalities, Apgar < 7, acidotic arterial pH, admission to the neonatal unit), preterm delivery, maternal complications, and type of delivery.

Results

No differences in perinatal mortality and morbidity were found between spontaneous twin pregnancies and twins resulting from assisted reproductive techniques. The rate of preterm labor was significantly higher in spontaneous twin pregnancies (75.2 versus 52%; p = 0.006). The incidence of gestational diabetes was significantly higher in twin pregnancies resulting from IVF than in spontaneous twin pregnancies (25.5 versus 9.7%;p = 0.01).

Conclusions

Perinatal and maternal outcomes in twin pregnancies resulting from IVF are similar to those of spontaneous twin pregnancies.