Influence of young maternal age and parity on term and preterm low birthweight

Data on 4496 singleton births to young women (19 years or less) are reported by maternal age and parity with birthweight and gestation cross-classified to yield rates of preterm and term low birthweight. After adjustment, the risk of preterm low birthweight was increased with very young maternity (15 years or less); preterm low birthweight and term low birthweight were each increased with young multiparity. These data suggest that the identification of factors associated with preterm birth and their incorporation into the prenatal care regimen may be important in improving pregnancy outcome in young women.     

The effects of sex, parity and maternal age on birth weights in a specialist hospital setting in Nigeria.

This study looked at the combined effects of maternal age, fetal sex and parity in a specialist hospital setting and compared it with already published figures obtained from public health-care data in Nigeria. The results show a relationship exists with bivariate analysis between these variables and birth weight, but with multivariate analysis the relationship proves to be spurious. Socio-economic status and maternal health were felt to be the most important considerations within the specialist hospital setting, as patients who attend are more likely to be of high socio-economic status and therefore on a higher income and better educated. This has a beneficial impact on maternal health and a positive outcome on birth weight.     

Effect of parity and advanced maternal age on obstetric outcome.

OBJECTIVES: To examine the effect of parity on obstetric outcome in women aged 40 years or older. METHODS: A retrospective cohort of 16 427 singleton pregnancies delivered between 1998 and 2001 was studied. Obstetric outcomes in women aged 40 years or older versus women younger than 40 years were compared for both nulliparous and multiparous women. RESULTS: Of the 15 727 pregnancies (95.7%) that satisfied the inclusion criteria, 606 (3.9%) were in women aged 40 years or older. Advanced age was independently associated with cesarean delivery, birth and spontaneous preterm labor before 37 weeks, and low birth weight neonates in nulliparous women, but only with preterm birth before 37 weeks and cesarean delivery in multiparous women. CONCLUSION: Obstetric outcome in women aged 40 years or older was influenced by parity. Cesarean delivery and preterm birth before 37 weeks were independently associated with older age irrespective of parity. Advanced age is a risk factor for preterm birth.     

Twinning in southern Israel. Seasonal variation and effects of ethnicity, maternal age and parity

Seasonality of births in southern Israel was examined in two populations, Jews and Bedouins, with distinctly different life-styles. The study included 1,444 twin births that occurred between the years 1970 and 1986. The peak month for the birth of monozygotic twins was September in both populations, while the maximum number of deliveries occurred in January for the Bedouins and August for the Jews. Of Jewish dizygotic twin births, higher rates were found from July to December. In addition, the peak months of singleton births in women aged 35 years and older and in women of high parity did not coincide with the peak months of multiple births. Maternal age and parity have been shown to greatly influence twin birth rates. The autumnal peak we found, which was independent of ethnic origin and its associated cultural and sociologic differences, was also independent of maternal age and parity and was consistent with findings in other populations in the northern hemisphere. That finding suggests that a seasonal factor, as yet undefined, affects the rates of multiple births.     

Maternal age and the likelihood of a maternal request for cesarean delivery: a 5-year population-based study

OBJECTIVE: The purpose of this study was to examine associations between maternal age and maternal request cesarean deliveries. STUDY DESIGN: Five-year population-based data from Taiwan (1997-2001) that covered 904,657 singleton deliveries without a clinical indication for cesarean delivery that were judged by the attending physician were subjected to multiple logistic regression, year-wise, to examine the association of maternal age with request cesarean delivery, adjusted for health care institutional characteristics. RESULTS: Request cesarean delivery rates steadily increased over the study period within each age group, disproportionately so among the 34+ age group. Women aged < 25 years were less likely than women aged 25 to 34 years (reference group) to request a cesarean delivery (odds ratio range, 0.67-0.88) and women aged 34+ were more likely than the reference group to have a request cesarean delivery (odds ratio range, 1.96-2.01), adjusted for health care institutional characteristics. CONCLUSION: Population-based data confirms the expectancy that request cesarean delivery propensity increases with maternal age.     

The impact of advanced maternal age and parity on obstetric and perinatal outcomes in singleton gestations

Objective  

To investigate the effect of advanced maternal age (AMA) separately in nulliparous and multiparous women on obstetric and perinatal outcomes in singleton gestations.     

Twinning in southern Israel; secular trends, ethnic variation and effects of maternal age and parity

Twin births in southern Israel between 1970 and 1986 were examined in the Jewish and Bedouin populations. An increase in dizygotic twinning in the whole population, largely due to an increase of rate in the Bedouin population was found. The dizygotic twinning rate in the Bedouin population rose until it reached the level found in the Jewish population. No change with time was found in the monozygotic twinning rates in either population. This suggests that while dizygotic twinning rates are influenced by environmental factors, the monozygotic twinning rates are not. The effects of maternal age and parity on dizygotic and monozygotic twinning rates differed in the two ethnic groups examined. In the Jewish population the dizygotic twinning rate was related to maternal age and parity, while in the Bedouins only maternal age affects the rate. The monozygotic twinning rate has an inverted U shape with maternal age in the Jewish population and is linearly related to maternal age in Bedouin women. No effect of parity on the Jewish monozygotic twinning rate is found but this rate is directly affected by parity in Bedouin women. The effects of maternal age and parity together were examined in both populations. Both maternal age and parity affected the twinning rates; however, the effects are not additive and no interaction between maternal age and parity was found.     

Impact of maternal age on preterm delivery and low birthweight: a hospital-based collaborative study of nulliparous Lebanese women in Greater Beirut.

OBJECTIVES: To analyze the impact of maternal age at first childbirth on the incidence of preterm delivery and low birthweight among single live births delivered to nulliparous Lebanese women in Greater Beirut. STUDY DESIGN: Eligible subjects were selected from a consecutive sample of neonatal admissions to nine National Collaborative Perinatal Network participating hospitals over a three-year period (April 1, 1999 to March 31, 2002). Chi-square tests and logistic regression analyses were applied. RESULTS: Out of 5556 nulliparous mothers, 5.4% had a preterm delivery and 5.2% a low-birthweight infant. In the multivariate analysis, preterm delivery was not significantly affected by old maternal age. Mothers aged 25 years or more remained a high-risk group for low birthweight even after controlling for potentially confounding characteristics. CONCLUSIONS: Maternal age at first childbirth above 25 years is an independent risk factor for low birthweight, but not for preterm delivery, an outcome influenced mainly by obstetric complications.     

The influence of maternal life stressors on breastfeeding outcomes: a US population-based study

Objective: The purpose of this study was to examine the contribution of maternal financial, emotional, traumatic, and partner-associated stressors on breastfeeding initiation and duration.

Methods: Data (216,756 records) from the Pregnancy Risk Assessment Monitoring System surveys were used in the analysis. Logistic regressions were conducted to estimate the magnitude and direction of associations between maternal stressors occurring in the 12 months prior to infant birth and both breastfeeding initiation and duration up to 4 weeks infant age.

Results: A substantial proportion of mothers (42%) reported having experienced one or two major stressors during the 12 months prior to the birth of their infant. Mothers who reported at least one major life stressor in the year before their baby was born were less likely to initiate breastfeeding and more likely to cease by 4 weeks infant age. Emotional and traumatic stressors were found to have the greatest impact on breastfeeding outcomes.

Conclusions: Findings support the design and implementation of screening protocols for major maternal life stressors during regularly scheduled prenatal and newborn visits. Screening for at-risk mothers may lead to more targeted anticipatory guidance and referral with positive effects on breastfeeding outcomes and overall well-being of the mothers and their families.     

The influence of maternal erythrocyte deformability on fetal growth, gestational age and birthweight.

The increase in blood viscosity during pregnancy reduces maternal-fetal blood flow, which can lead to fetal hypoxia and acidosis. These factors have been related to a reduction in fetal growth and to premature births. We carried out a longitudinal study of 36 normal-term gestations at different stages of the pregnancy. We analyzed the erythocyte deformability, the intraerythocyte viscosity and the plasma viscosity in the mother, as well as the relation of these parameters to fetal growth (biparietral diameter (BPD) and length of the femur), birthweight, gestational age at birth and the Agpar score. The results obtained were as follows: from weeks 25 to 36 of pregnancy (30.9 (SD 2 weeks)) there occurs a significant increase in maternal erythocyte rigidity (p < 0.05) (despite the compensatory decrease in intracellular viscosity). This increase is very significantly related to the fetal biparietral diameter (r = -0.50, p < 0.01), the length of the fetal femur (r = -0.48, p < 0.02), gestational age at birth (r = -0.73, p < 0.0001, birthweight (r = -0.63, p < 0.001) and the Agpar score 5 minutes after birth (r = 0.67, p < 0.001). Our conclusions are that the reduction in erythocyte deformability (which we attribute to alterations in the fluidity or elasticity of its membrane) and the factors that increase the aggregation capacity of the red cells (modulators of blood viscosity and of blood flow in the placental intervillous space) are risk factors for reduced fetal growth, lower birthweight and lower gestational age at birth. By avoiding maternal hematocrit levels higher than 36% we could improve uteroplacental perfusion, fetal growth and perinatal results.     

Accuracy and correlates of maternal recall of birthweight and gestational age

Objective  To determine the accuracy of maternal recall of children birthweight (BW) and gestational age (GA), using the Danish Medical Birth Register (DBR) as reference and to examine the reliability of recalled BW and its potential correlates.
Design  Comparison of data from the DBR and the European Youth Heart Study (EYHS).
Setting  Schools in Odense, Denmark.
Population  A total of 1271 and 678 mothers of school children participated with information in the accuracy studies of BW and GA, respectively. The reliability sample of BW was composed of 359 women.
Method  The agreement between the two sources was evaluated by mean differences (MD), intraclass correlation coefficient (ICC) and Bland–Altman's plots. The misclassification of the various BW and GA categories were also estimated.
Main outcome measures  Differences between recalled and registered BW and GA.
Results  There was high agreement between recalled and registered BW (MD =−0.2 g; ICC = 0.94) and GA (MD = 0.3 weeks; ICC = 0.76). Only 1.6% of BW would have been misclassified into low, normal or high BW and 16.5% of GA would have been misclassified into preterm, term or post-term based on maternal recall. The logistic regression revealed that the most important variables in the discordance between recalled and registered BW were ethnicity and parity. Maternal recall of BW was highly reliable (MD =−5.5 g; ICC = 0.93), and reliability remained high across subgroups.
Conclusion  Maternal recall of BW and GA seems to be sufficiently accurate for clinical and epidemiological use.     

Preeclampsia in twin gestations: Association with IVF treatments,parity and maternal age

Objective.?To identify maternal factors that increase the risk of preeclampsia in twin gestations and to investigate whether twins conceived by in vitro fertilization (IVF) lead to an increased risk of preeclampsia development.

Materials and methods.?A retrospective population-based cohort study of twin deliveries was performed. Maternal characteristics and perinatal outcomes were evaluated. Patients' data were obtained from a computerized database and analyzed using SPSS statistical package.

Results.?During the study period there were 2628 twin deliveries, and of these 3.1% had severe preeclampsia and 6.16% mild preeclampsia. Patients with severe preeclampsia were more likely to be primiparous, and to have significantly higher frequency of chronic hypertension, gestational diabetes mellitus (GDM), IVF treatments, cesarean delivery, preterm delivery and twin discordancy than in the normotensive patients. Chronic hypertension, pirimiparity, twin discordancy and maternal age were independent risk factors for the development of preeclampsia. In a multivariate regression model including IVF treatment, parity and maternal age as risk factors for preeclampsia, women younger than 35 years that conceived following IVF treatments had an independent risk factor for the development of preeclampsia.

Conclusion.?IVF treatments in primiparous patients and age younger than 35 years are independent risk factors for preeclampsia. Twin discordancy is an additional independent risk factor for the occurrence of preeclampsia.     

The trend in the relationship of advanced maternal age to preterm birth and low birthweight

Purpose: As women in developed countries tend to delay childbearing, it becomes more important to understand the relationship of advanced maternal age to birth outcomes. We aimed to estimate the trend in the relationship of advanced maternal age to preterm birth and low birthweight.

Materials and methods: We analysed 4,264,417 ethnically homogeneous, singleton firstborns, born in hospitals to married couples in South Korea in 1997–2014. We regressed an indicator for preterm birth or low birthweight on advanced maternal age, the baby’s sex, advanced paternal age, and a set of socioeconomic status (SES) variables by year. We then collected the coefficient on advanced maternal age and charted its trend. We repeated the same procedure for 4,153,313?second- and third births.

Results: When we controlled for only the baby’s sex, the relationship between advanced maternal age and preterm birth dramatically weakened in the 2000s and slightly more thereafter: being an older mother was related to a 3.5% point increase in preterm birth in the late 1990s, but this figure decreased to less than 2% points by the early 2010s. Controlling for advanced paternal age slightly decreased the relationship and controlling for SES hardly affected the relationship. We obtained almost the same results for low birthweight. Second- and third-borns exhibited a declining, much weaker influence of advanced maternal age on the birth outcomes.

Conclusions: In relative terms, mothers of advanced age were more likely to deliver preterm and low birthweight babies than younger mothers. In absolute terms, however, the risk was small in the 1990s and much smaller in the early 2010s.     

The effect of maternal age, parity, and prenatal care on perinatal outcome in adolescent mothers

Maternal age and prenatal care were found to influence the risk for having a small-for-gestational age infant in white adolescent mothers who had both one and two previous live births. However, poor care exerted a relatively stronger affect than young age for primiparous mothers, while the reverse was found for multiparous mothers. Moreover, for women with first births, there was an interaction between variables in that early prenatal care promoted better pregnancy outcome for younger teenagers than for older teens or adults. These results indicate that the perinatal risks of adolescent pregnancy are affected by both physiologic factors and prenatal care.     

Gestational age-specific neonatal morbidity among pregnancies complicated by advanced maternal age: a population-based retrospective cohort study

Objective: Compare significant neonatal morbidity frequency differences in advanced maternal age (AMA) versus non-AMA pregnancies, assessing which gestational week is associated with the lowest morbidity risk.

Methods: Population-based retrospective cohort study. Adverse neonatal outcome frequency differences were stratified by each week of gestation. Multivariate logistic regression estimated the relative risk (RR) of composite neonatal morbidity for women aged 35–39, 40–44, 45–49 and 50–55 versus 18–34 years, adjusted sequentially for relevant risk factors.

Results: Neonatal morbidity decreased with each advancing week of term gestation, lowest at 39 weeks for all the groups. Adverse neonatal outcome risk for births to AMA women increased at 40 weeks: 35–39 years _adjRR 1.12 [1.01–1.24] and ≥40 years 1.24 [1.01–1.52]. Each older maternal age category had increased risk for overall neonatal morbidity: 35–39 years _adjRR 1.11 [95% CI 1.08–1.15], 40–44 years 1.21 [95% CI 1.14–1.29] and 45–49 years 1.34 [95% CI 1.05–1.69].

Conclusions: Lowest neonatal morbidity risk is at 39-week gestation with a significantly increased risk observed thereafter, especially in women ≥40 years.     

Effect of maternal age on the risk of stillbirth: a population-based cohort study on 37 million births in the United States

The objective of our study was to evaluate the incidence and effect of maternal age on the risk of stillbirth. We conducted a population-based cohort study using the Centers for Disease Control and Prevention's "Linked Birth-Infant Death" and "Fetal Death" data files. We excluded all births of gestational age under 24 weeks and those with reported congenital malformations. We estimated the adjusted effect of maternal age on the risk of stillbirth using logistic regression analysis. There were 37,504,230 births that met study criteria, of which 130,353 (3.5/1,000) were stillbirths. Rates of stillbirth remained constant throughout the 10 years. As compared with women between the ages of 25 and 30, decreasing maternal age was associated with the following risk of stillbirth: odds ratio (OR) 0.95 (95% confidence interval [CI] 0.93 to 0.97) for ages 20 to 25; OR 0.97 (95% CI 0.94 to 0.99) for ages 15 to 20; and OR 1.32 (95% CI 1.18 to 1.47) for ages <15. Increasing maternal age was associated with an increasing risk of stillbirth: OR 1.02 (95% CI 0.99 to 1.04) for ages 30 to 35, OR 1.25 (95% CI 1.21 to 1.28) for ages 35 to 40, OR 1.60 (95% CI 1.53 to 1.67) for ages 40 to 45, and OR 2.22 (95% CI 1.91 to 2.53) for ages >45. Although the overall risk is low, the risk of stillbirth increases considerably in women at the extremes of the reproductive age spectrum. Antenatal surveillance may be justified in these women.