Maternal age at birth and daughter's fecundability

Association of maternal risk factors with fetal aneuploidy and the accuracy of prenatal aneuploidy screening: a correlation analysis based on 12,186 karyotype reports

BACKGROUND

NIPT is becoming increasingly important as its use becomes more widespread in China. More details are urgently needed on the correlation between maternal risk factors and fetal aneuploidy, and how these factors affect the accuracy of prenatal aneuploidy screening.

METHODS

Information on the pregnant women was collected, including maternal age, gestational age, specific medical history and results of prenatal aneuploidy screening. Additionally, the OR, validity and predictive value were also calculated.

RESULTS

A total of 12,186 analysable karyotype reports were collected with 372 (3.05%) fetal aneuploidies, including 161 (1.32%) T21, 81 (0.66%) T18, 41 (0.34%) T13 and 89 (0.73%) SCAs. The OR was highest for maternal age less than 20 years (6.65), followed by over 40 years (3.59) and 35-39 years (2.48). T13 (16.95) and T18 (9.40) were more frequent in the over-40 group (P < 0.01); T13 (3.62/5.76) and SCAs (2.49/3.95) in the 35-39 group (P < 0.01). Cases with a history of fetal malformation had the highest OR (35.94), followed by RSA (13.08): the former was more likely to have T13 (50.65) (P < 0.01) and the latter more likely to have T18 (20.50) (P < 0.01). The sensitivity of primary screening was 73.24% and the NPV was 98.23%. The TPR for NIPT was 100.00% and the respective PPVs for T21, T18, T13 and SCAs were 89.92, 69.77, 53.49 and 43.24%, respectively. The accuracy of NIPT increased with increasing gestational age (0.81). In contrast, the accuracy of NIPT decreased with maternal age (1.12) and IVF-ET history (4.15).

CONCLUSIONS

①Pregnant patients with maternal age below 20 years had higher risk of aneuploidy, especially in T13; ②A history of fetal malformations is more risky than RSA, with the former more likely to have T13 and the latter more likely to have T18; ③Primary screening essentially achieves the goal of identifying a normal karyotype, and NIPT can accurately screen for fetal aneuploidy; ④A number of maternal risk factors may influence the accuracy of NIPT diagnosis, including older age, premature testing, or a history of IVF-ET. In conclusion, this study provides a reliable theoretical basis for optimizing prenatal aneuploidy screening strategies and improving population quality.

Approaches for Assessing Effects of Exposures on Human Fertility

BACKGROUND

Fecundability (conception rate per menstrual cycle) varies among non-contracepting couples. Time-to-pregnancy studies can identify exposures contributing to that variability, using three designs: incident cohort, prevalent cohort, and retrospective. Typically, researchers then apply semi-parametric, generalized linear time-to-pregnancy models to data, with either a log or a logit "link," to estimate either a fecundability ratio (FR) or a fecundability odds ratio (FOR). The ongoing-attempt study design can also be informative.

METHODS

We consider a different generalized linear model, based on an inverse link. It models the heterogeneity as beta distributed and enables estimation of both the FR and FOR, defined based on population mean fecundabilities, without requiring constancy across attempt time. Under an ongoing-attempt design, the parameter associated with a dichotomous exposure has no clear meaning with a log or a logit link, but under the proposed approach estimates the ratio of the two average times to pregnancy. Basing simulations on conception rates from a large study, we compare the three analytic approaches for confidence interval coverage and power. We also assess the performance of a commonly used method for verifying the constancy of FOR or FR across time.

RESULTS

The inverse-link approach had slightly less power than the others, but its estimates maintained nominal confidence interval coverage under nonconstancy. A popular method for testing constancy across time for the FR and FOR had poor power.

CONCLUSIONS

The inverse-link analysis offers a useful alternative to the usual methods, with estimation performance that generalizes to the ongoing-attempt design and does not require hard-to-verify constancy assumptions.

Intergenerational trends in reproduction: Infertility and pregnancy loss

This review article summarises the evidence for intergenerational trends observed to date within infertility and pregnancy loss. There appears to be evidence of intergenerational trends between mothers and daughters for the age at menopause, endometriosis, polycystic ovarian syndrome (PCOS), male factor infertility and miscarriage. At present, there is no evidence for a predisposition to stillbirth between mothers and daughters. One study found an association with familial predisposition for ectopic pregnancy. Very few studies have considered the potential for paternal transmission of risk of infertility or pregnancy loss. The majority of studies to date have significant limitations because of their observational design, risk of recall bias and risk of confounding. Therefore, high-quality well-designed research, with multi-centre collaboration and utilisation of registry-based data sources and individual patient data, is needed to understand whether infertility and pregnancy loss may have heritable factors. Epidemiological findings need to be followed up and investigated with translational research to determine the possible causalities as well as any implications for clinical practice.

Reproductive outcomes in women and men conceived by assisted reproductive technologies in Norway: prospective registry based study

Objectives

To determine whether the perinatal outcomes of women or men who were conceived by assisted reproductive technologies are different compared with their peers who were naturally conceived.

Design

Prospective registry based study.

Setting

Medical Birth Registry of Norway.

Participants

People born in Norway between 1984 and 2002 with a registered pregnancy by the end of 2021.

Exposure

People who were conceived by assisted reproductive technologies and have had a registered pregnancy.

Main outcome measures

Comparing pregnancies and births of people who were conceived by assisted reproductive technologies and people who were naturally conceived, we assessed mean birth weight, gestational age, and placental weight by linear regression, additionally, the odds of congenital malformations, a low 5 min Apgar score (<7), transfer to a neonatal intensive care unit, delivery by caesarean section, use of assisted reproductive technologies, hypertensive disorders of pregnancy and pre-eclampsia, preterm birth, and offspring sex, by logistic regression. The occurrence of any registered pregnancy from people aged 14 years until age at the end of follow-up was assessed using Cox proportional regression for both groups.

Results

Among 1 092 151 people born in Norway from 1984 to 2002, 180 652 were registered at least once as mothers, and 137 530 as fathers. Of these, 399 men and 553 women were conceived by assisted reproductive technologies. People who were conceived by assisted reproductive technologies had little evidence of increased risk of adverse outcomes in their own pregnancies, increased use of assisted reproductive technologies, or any difference in mean birth weight, placental weight, or gestational age. The only exception was for an increased risk of the neonate having a low Apgar score at 5 min (adjusted odds ratio 1.86 (95% confidence interval 1.20 to 2.89)) among women who were conceived by assisted reproductive technologies. Odds were slightly decreased of having a boy among mothers conceived by assisted reproductive technologies (odds ratio 0.79 (95% confidence interval 0.67 to 0.93)). People conceived by assisted reproductive technologies were slightly less likely to have a registered pregnancy within the follow-up period (women, adjusted hazard ratio 0.88 (95% CI 0.81 to 0.96); men, 0.91 (0.83 to 1.01)).

Conclusions

People conceived by assisted reproductive technologies were not at increased risk of obstetric or perinatal complications when becoming parents. The proportion of people conceived by assisted reproductive technologies with a registered pregnancy was lower than among people who were naturally conceived, but a longer follow-up is required to fully assess their fertility and reproductive history.