Human chorionic gonadotropin in cord blood and peripheral maternal blood in singleton and twin pregnancies at delivery

The influence of fetal sex on human chorionic gonadotropin (hCG) in cord and peripheral maternal blood was studied at delivery in 57 twin and 66 singleton uncomplicated pregnancies. In twin pregnancies the hCG levels were about twice as high in female-female and in female-male vis-à-vis male-male combinations in both maternal and cord blood. In singleton pregnancies the hCG levels were significantly higher in maternal and in cord blood in cases of female vis-à-vis male infants. The ratio of maternal hCG/placental weight was also highest in the twin pregnancies when one or both infants were female. This suggests a "female effect", possibly genetically based.     

Gestational duration and birth weight for twins related to fetal sex.

It has been postulated that male twin pregnancies, in contrast to male singleton pregnancies, differ in some distinctive biologic sense, leading to a shorter gestational duration and a lower individual birth weight than is the case in female twin pregnancies. To test this hypothesis in a relatively large dataset, information on gestational duration and birth weight for nearly all twins born in Sweden during a 4-year period (n = 3,472 twin pairs) was collected from the Medical Birth Registry, National Board of Health and Welfare. Included in the Medical Birth Registry are all pregnancies with a duration of at least 28 completed gestational weeks, or less if the newborns are alive at birth. Male-male pregnancies had a gestational duration similar to female-female pregnancies (median difference less than 2 days). The proportions of twins with a gestational age less than 36 weeks did not differ between male-male and female-female twin pregnancies (27.3 vs. 25.3%; chi 2 = 2.2, p greater than 0.05). Male-male pairs were heavier than female-female pairs (median difference 0.1 kg), and a significantly higher proportion of female-female twin pairs weighted less than 2,500 g (45.0 vs. 39.2%; chi 2 = 17.7, p less than 0.001). The results of this study in an unselected relatively large twin population seem to indicate that fetal sex does not influence gestational duration to any significant extent. Males are heavier than females indicating that the sex has a similar effect on birth weight in twin and in singleton pregnancy.     

Preeclampsia in Twin Pregnancy-Severity and Pathogenesis

The incidence of preeclampsia in a consecutive series of 642 twin pregnancies was 25.9% compared with 9.7% in singleton pregnancies (p less than 0.001); in primiparas it was 35.2% and in multiparas 20.4% (p less than 0.001). Preeclampsia in twin pregnancies was more commonly of early onset (p less than 0.001) and the maternal disease more severe as assessed by the incidences of severe hypertension (p less than 0.001), proteinuria (p less than 0.004), and eclampsia (p less than 0.01). There were 1 maternal and 12 perinatal deaths. Oestriol excretion before the emergence of preeclampsia was lower in patients with severe compared with milder preeclampsia (p less than 0.05) as was plasma glucose concentration (p less than 0.05). Mean birth and placental weights according to gestation, tended to be lower in the severe group compared with uncomplicated cases and those with milder preeclampsia, as were also the placental-fetal weight ratios. The similarity of results with those already reported for singleton pregnancy suggested a similar pathogenesis for preeclampsia in twin and singleton pregnancies.     

The amniotic fluid index in normal twin pregnancies

OBJECTIVE: We sought to investigate the amniotic fluid index for individual gestational sacs of twin pregnancies. STUDY DESIGN: Four hundred eighty-eight patients with normal diamniotic twins were examined between 14 and 40 weeks' gestation. The dividing membrane between twin fetuses was identified. An amniotic fluid index was then obtained for each gestational sac. RESULTS: The median amniotic fluid index in individual twin gestational sacs rises slowly from 14 to 16 weeks' gestation to 23 to 28 weeks' gestation and then gradually declines. The median amniotic fluid index values by gestational age for twin A and twin B are not statistically different. Although twin pregnancies have a slightly lower median amniotic fluid index value than singleton pregnancies, the difference is also not statistically significant. CONCLUSION: Individual amniotic fluid indices can be obtained in twin pregnancies, and the values are comparable with those of singleton gestations.     

Human chorionic gonadotropin and testosterone in normal and preeclamptic pregnancies in relation to fetal sex

OBJECTIVE: The aim of the present study was to evaluate the effects of fetal gender on serum human chorionic gonadotropin (hCG) and testosterone in normotensive and preeclamptic pregnancies. METHODS: The study consisted of 137 women with singleton pregnancies in the third trimester. Seventy-three pregnancies were uncomplicated; among those were 35 male and 38 female fetuses. Sixty-four pregnancies were complicated by preeclampsia; among those were 33 male and 31 female fetuses. Human chorionic gonadotropin and total testosterone were measured in maternal peripheral blood. RESULTS: In male-bearing pregnancies, maternal hCG and testosterone serum levels were significantly higher in preeclamptic than normotensive mothers (P <.001). In female-bearing pregnancies, testosterone levels were significantly higher in preeclamptic than normotensive mothers (P <.001), whereas the hCG levels were not significantly different. Male-bearing preeclamptic women had significantly higher testosterone levels than female-bearing preeclamptic women (P <.02), whereas the hCG levels were not significantly different. In uncomplicated pregnancies the hCG levels were significantly higher in female-bearing than in male-bearing mothers (P <.005), whereas the testosterone levels were not significantly different. CONCLUSION: In preeclamptic pregnancies with male fetuses, the maternal serum hCG levels were significantly higher than in uncomplicated pregnancies. Total testosterone levels were significantly higher in pregnancies with either gender and significantly higher in male-bearing than in female-bearing pregnancies. This may indicate an androgen influence on the pathophysiologic mechanism of preeclampsia.     

Coagulation-fibrinolysis is more enhanced in twin than in singleton pregnancies

AIMS: To examine whether coagulation-fibrinolysis in late pregnancy in women with twin pregnancies is more pronounced than in women with singleton pregnancies. PATIENTS AND METHODS: The plasma levels of D-dimer, fibrinogen/fibrin degradation products (FDP), and fibrinogen, the platelet count, and the antithrombin activity were assessed from 3 weeks before delivery until postpartum day 7 in 48 women (24 singleton and 24 twin pregnancies) without preeclampsia who underwent cesarean sections. RESULTS: Women with singleton or twin pregnancies gave birth at 37.3+/-1.2 weeks or 35.2+/-1.4 weeks, respectively. Compared with singleton mothers, prenatal D-dimer and FDP levels were consistently and significantly higher among women with twin pregnancies. A significantly larger proportion of twin mothers exhibited prenatal levels of D-dimer >5.0 microg/mL, FDP >10.0 microg/mL, fibrinogen <420 mg/mL and antithrombin activity <70%. In addition, prenatal antithrombin activity in plasma was significantly lower. CONCLUSIONS: Coagulation-fibrinolysis is more enhanced in women with twin gestation than in women with singleton gestation.     

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.     

SRY-specific cell free fetal DNA in maternal plasma in twin pregnancies throughout gestation

Objectives

Levels of SRY-specific cell free fetal DNA (SRY-cffDNA) in maternal plasma were investigated in twin pregnancies with two male fetuses versus one male and one female fetus and singleton male pregnancies during second and third trimester. The aim was to evaluate at which gestational age the amount of SRY-cffDNA reflects the number of fetuses and placentas respectively.

Methods

251 venous blood samples were analyzed from a total of 178 women with male or mixed-gender twin pregnancies and male singleton pregnancies in the second and the third trimester. The concentration of SRY-cffDNA was determined by quantitative real time PCR using the Y-chromosome specific SRY assay. For statistical analysis these three groups were divided into four subgroups according to their gestational age.

Results

During second trimester levels of SRY-cffDNA showed no differences between twin and singleton pregnancies. After 28 weeks SRY-cffDNA of male twin pregnancies was significantly increased compared to singleton male pregnancies and mixed-gender twin pregnancies with no differences between the latter two.

Conclusion

The level of SRY-cffDNA in maternal serum of twin pregnancies reflects the number of fetuses only during the third trimester. Hence its use as a diagnostic tool for complications related to altered SRY-cffDNA levels in twin pregnancies should be evaluated at different weeks of gestation, especially during the second trimester.     

Risk factors for preeclampsia in Japanese twin pregnancies: comparison with those in singleton pregnancies

Objective  To identify the factors associated with the increased risk of developing preeclampsia in twin pregnancies compared with those in singleton pregnancies. Methods  We reviewed the obstetric records of all deliveries at ≥22 weeks’ gestation managed at the Japanese Red Cross Katsushika Maternity Hospital between 2001 and 2007. Results  The incidence of preeclampsia in the twin pregnancies (7.6%: 45 in 593) was significantly higher than that in the singleton pregnancies (1.7%: 196 in 11,311; P < 0.01). In singleton pregnancies, the developing preeclampsia was associated with maternal age at ≥35 years, primiparity, maternal BMI ≥25 before pregnancy, history of infertility therapies such as IVF and having a history of previous preeclampsia. In twin pregnancies, however, the developing preeclampsia was not associated with these variables. Conclusions  In Japanese women, the factors reported to be associated with the increased risk of preeclampsia in singleton pregnancies may not alter the increased risk of preeclampsia in twin pregnancies.     

Fetal middle cerebral artery Doppler waveforms in twin-twin transfusion syndrome

The aim of this study was to compare the fetal middle cerebral artery (MCA) Doppler waveforms in growth-retarded twin fetuses with (n = 11) and without (n = 24) twin-twin transfusion syndrome (TTTS). Umbilical artery (UA) and fetal MCA Doppler velocity waveforms were recorded on admission. The mean values of the UA pulsatility index (PI) of smaller twin fetuses with and without TTTS were significantly higher than those of normal singleton pregnancies. The mean values of the MCA PI of smaller twin fetuses in the TTTS group (+0.7 +/- 1 SD) were significantly higher than those of normal singleton pregnancies on admission, and these levels did not markedly change following amniocentesis. On the other hand, the values of the MCA of the growth-retarded fetuses without TTTS (-0.9 +/- 1 SD) were significantly lower than those of normal singleton pregnancies. Our findings suggest that measurement of fetal MCA PI is a useful method to assess growth-retarded fetuses in monochorionic twin pregnancies. Copyright Copyright 1999 S. Karger AG, Basel     

Biparietal diameter growth in uncomplicated twin gestation

Ninety-six fetuses of uncomplicated concordant twin pregnancies were monitored by ultrasonic cephalometry from 13 to 38 weeks gestation. The biparietal diameter (BPD) growth of 96 twin fetuses was then compared to a sample of 299 uncomplicated, appropriate-for-gestational-age singleton pregnancies. Regression analysis applied to these measurements of BPD on twin and singleton pregnancies showed no significant difference in biparietal diameter between uncomplicated singleton and twin pregnancies. It is concluded that charts derived from singleton pregnancies may be reliably used for estimation of gestational age of twins.     

Glucose Tolerance in Twin Pregnancy

Summary: Over a 10-year period, 50 g oral glucose tolerance tests were performed in 288 patients with twin pregnancies and 20,030 with singleton pregnancies. In multiple pregnancies the fasting blood glucose value was significantly reduced (P<0.001), but the values at 1, 2 and 3 hours were not significantly different from those in singleton pregnancies. The incidences of both gestational diabetes (5.6%) and gestational hypoglycaemia (3.9%) in twin pregnancies were more than double those in singleton pregnancies (2.5% and 1.7%, respectively) (P<0.01). As the risk of perinatal death is increased in these patients, glucose tolerance tests should be performed in all patients with twin pregnancies.     

Early anti-angiogenic proteins expression in amniotic fluid of twin fetuses

Multiple pregnancies are thought to be associated with a high incidence of perinatal complications such as preterm labor, preeclampsia and low birth weight. But the true mechanisms of these obstetric complications are still uncertain. The components of amniotic fluid reflect the pathophysiology features of the fetus. Amniotic fluid soluble fms-like tyrosine kinase 1(sFLT1), soluble endoglin (sENG), and adiponectin reflect the oxidative stress and pro-inflammatory status and are associated with preeclampsia and fetal growth restriction. We prospectively collected amniotic fluids during amniocentesis from singleton and twin pregnancies. Samples were analyzed for levels of sFLT1, sENG, and adiponectin by enzyme-linked immunosorbent assay. The levels of sENG and sFLT1 were significantly increased in twin pregnancies. Adiponectin was not significantly different between the two groups. These findings would suggest that twin fetuses suffer from more oxidative stress and pro-inflammatory status from the early trimesters.     

Comparative maternal lactate-pyruvate ratios in singleton and twin pregnancies and in babies delivered at term.

The lactate-pyruvate (L/P) ratio was used for assessment of anaerobic metabolism, hypoxia or oxygen debt in uterine contractile muscle during labour and immediately after parturition. The mean blood lactate level was significantly higher in mothers with twin pregnancies (P<0.001) than in singleton pregnancies at term. L/P ratios were markedly elevated in established labour both in mothers of singleton as well as in mothers of twin pregnancies and were also higher in cord blood of the twins than those of singleton babies (P<0.001). The twins delivered second had higher L/P ratios (P<0.05) than the leading twins.     

单、双胎妊娠并发子痫前期不良妊娠结局的荟萃分析

目的探讨单、双胎妊娠并发子痫前期的孕妇与围产儿不良结局发病率差异。 方法检索PubMed、Web of Science、中国生物医学文献数据库、中国学术文献总库、万方和维普中文数据库中2000年1月至2017年12月国内外发表的关于单、双胎妊娠并发子痫前期妊娠结局的研究。采用RevMan 5.3与Stata 12.0软件对资料进行荟萃分析,采用OR值及相应的95%CI评价不良结局与双胎妊娠并发子痫前期的相关性。 结果纳入10篇文献,共692例双胎妊娠合并子痫前期,3101例单胎妊娠合并子痫前期。双胎妊娠合并子痫前期组发病率高于单胎妊娠合并子痫前期：胎盘早剥OR＝2.16,95%CI为1.40～3.36;产后出血OR＝2.90, 95%CI为2.03～4.15;心功能衰竭OR＝3.73, 95%CI为2.10～6.63 ;肺水肿OR＝2.76, 95%CI为1.04～7.27;剖宫产OR＝2.27, 95%CI为1.58～3.26;胎膜早破OR＝2.99, 95%CI为1.64～5.47;早产OR＝6.24,95%CI为4.16～9.38,新生儿重症监护病房转入率OR＝2.33, 95%CI为1.66～3.26。 结论双胎妊娠合并子痫前期的不良妊娠结局包括胎盘早剥、产后出血、心功能衰竭、肺水肿、剖宫产、胎膜早破、早产和新生儿重症监护病房转入的发病率比单胎妊娠合并子痫前期高。     

Hypertensive disorders in twin versus singleton gestations. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

OBJECTIVE: This study was undertaken to compare rates and severity of gestational hypertension and preeclampsia, as well as perinatal outcomes when these complications develop, between women with twin gestations and those with singleton gestations. STUDY DESIGN: This was a secondary analysis of prospective data from women with twin (n = 684) and singleton (n = 2946) gestations enrolled in two separate multicenter trials of low-dose aspirin for prevention of preeclampsia. End points were rates of gestational hypertension, rates of preeclampsia, and perinatal outcomes among women with hypertensive disorders. RESULTS: Women with twin gestations had higher rates of gestational hypertension (relative risk, 2.04; 95% confidence interval, 1.60-2.59) and preeclampsia (relative risk, 2. 62; 95% confidence interval, 2.03-3.38). In addition, women with gestational hypertension during twin gestations had higher rates of preterm delivery at both <37 weeks' gestation (51.1% vs 5.9%; P <. 0001) and <35 weeks' gestation (18.2% vs 1.6%; P <.0001) and also had higher rates of small-for-gestational-age infants (14.8% vs 7. 0%; P =.04). Moreover, when outcomes associated with preeclampsia were compared, women with twin gestations had significantly higher rates of preterm delivery at <37 weeks' gestation (66.7% vs 19.6%; P <.0001), preterm delivery at <35 weeks' gestation (34.5% vs 6.3%; P <.0001), and abruptio placentae (4.7% vs 0.7%; P =.07). In contrast, among women with twin pregnancies, those who remained normotensive had more adverse neonatal outcomes than did those in whom hypertensive complications developed. CONCLUSIONS: Rates for both gestational hypertension and preeclampsia are significantly higher among women with twin gestations than among those with singleton gestations. Moreover, women with twin pregnancies and hypertensive complications have higher rates of adverse neonatal outcomes than do those with singleton pregnancies.     

Advanced ultrasonic placental maturation in twin pregnancies

The mean length of twin pregnancies is shorter than that of singleton pregnancies. The possibility that the shorter gestation of twins is associated with advanced fetal maturational changes was studied in relation to placental maturation. For this purpose, the sonographically determined placental gradings of 158 twin pregnancies and 474 singleton pregnancies were compared at different gestational ages. The percent distributions of placental grades, from I to III, were significantly different throughout the third trimester, with a preponderance of Grade III placentas in the twin group (p less than 0.001). Considering the reported association of Grade III placentas with advanced gestation as well as fetal lung maturity, the present study suggests earlier maturational changes in twin fetuses compared with singleton fetuses.     

Risk for gestational diabetes and hypertension for women with twin pregnancy compared to singleton pregnancy

OBJECTIVES. This study was undertaken to determine the incidence of pregnancy induced hypertension (PIH) and gestational diabetes (GDM) in twin pregnancies (TP) in comparison with singleton pregnancies (SP), and to test whether TP with GDM have a higher risk than TP without GDM, as is known to be the case in SP. MATERIALS AND METHODS. Eighty-nine patients with TP who sought prenatal care between 1 September 1994 and 30 October 1997, were asked to participate. One hundred and seventy-eight of the 1,416 patients were matched in a 1:2 ratio by age, body-mass-index, parity, gestational age at screening, and ethnicity with a singleton pregnancy from our database dating from the same period. The diagnosis "hypertension" or "preeclampsia" was made using clinical criteria including a repeated blood pressure above 140/90 mm Hg. Maternal and fetal outcome were compared between SP and TP, between TP with and without pathological screening, between TP with and without GDM. RESULTS. Patients with TP did not have a higher rate of GDM but of PIH (GDM 3.4% vs. 3.4%, p=0.63; PIH 2.8% vs. 9.0%, p=0.036). Expectant mothers of twins whose glucose screening test was pathological have a higher incidence of hypertension than those whose screening test was normal (17.9% vs. 4.9%, p=0.048). Twins of gestational diabetics have a higher rate of admission to the neonatal intensive care unit than twins of healthy pregnant patients (100% vs. 31%, p=0.028). CONCLUSIONS. TP are associated with a higher risk of hypertension than SP but not for GDM. Patients expecting twins who show a carbohydrate intolerance are at a higher risk for hypertension and fetal diabetes-associated complications.     

Maternal plasma homocysteine concentrations are not increased in twin pregnancies.

OBJECTIVE(S): We tested the hypothesis that twin pregnancies would lead to increased maternal plasma homocysteine. We further hypothesized that twin pregnancies complicated by preeclampsia would have increased plasma homocysteine compared to twin pregnancies without preeclampsia and normal singleton pregnancies. METHODS: Plasma was collected at delivery from 127 nulliparous subjects: 57 women with normal singleton pregnancies, 39 women with singleton and preeclampsia, 17 women with uncomplicated twin pregnancies, and 14 women with twins and preeclampsia. Subjects were group matched for prepregnancy body mass index (BMI) and race. Plasma homocysteine was analyzed by high pressure liquid chromatography (HPLC) with fluorescence detection, and plasma folic acid was measured by radio immunoassay (RIA). RESULTS: The mean plasma concentration of homocysteine was significantly increased in all women with preeclampsia (7.4+/-2.9 microM) compared to all normal pregnant women (5.9+/-2.1 microM, p=0.002). However, homocysteine was not significantly increased in all women with twins (6.7+/-2.1 microM) compared to all women with singleton pregnancies (6.5+/-2.7 microM, p=0.61). In addition, women with twins and preeclampsia did not have increased homocysteine (6.8+/-2.1 microM) compared to women with twins and normal pregnancy (6.7+/-2.1 microM, p=0.72). As expected, because of extra supplementation, plasma folic acid was significantly increased in women with twins (27.9+/-11.6 ng/mL) compared to women with singleton pregnancies (20.8+/-8.5 ng/mL, p=0.0003). However, folic acid was not different between preeclamptics and controls (23.5+/-10.8 vs. 21.9+/-9.2 ng/mL respectively, p=0.36). Lastly, there was a significant inverse correlation between homocysteine and folic acid among all the subjects (r2=- 0.053, p< 0.01), and this correlation persisted in the women with singleton pregnancies (r2=- 0.078, p< 0.01), but was lost in the twins (r2=- 0.073, p=0.14). CONCLUSIONS: With contemporary management including increased folic acid supplementation, plasma homocysteine is not increased in twin pregnancies with or without preeclampsia.     

Intrauterine breathing movements and fetal presentation

Fetal breathing movements in 14 twin pregnancies were examined with ultrasonic technique. The twin fetuses I in cephalic presentation showed a significantly higher percentage of apnea and periodic breathing compared with twin fetuses II. No such difference was found in twin pairs with Twin ti in breech presentation. Also in the control group of 27 singleton pregnancies, the fetuses in cephalic presentation had a higher incidence of apnea and periodic breathing than those in breech presentation. The position of the fetus seems to be decisive for the character of the breathing movements before birth.