Reduced subsequent births reported after severe maternal morbidity

Reduced subsequent births reported after severe maternal morbidity | Image Credit: © Dimid - © Dimid - stock.adobe.com.

Women with severe maternal morbidity (SMM) during their first pregnancy are less likely to undergo subsequent pregnancies, according to a recent study published in JAMA.¹

SMM is defined as a life-threatening event occurring during pregnancy, delivery, and up to 42 days postpartum. A composite SMM rate of 270.2 per 10,000 deliveries was reported in Sweden from 1999 to 2019.

Persistent health issues may occur in women following SMM. These include reproductive challenges that may impact future reproductive ability. Small studies have found a potential association between SMM at first birth and increased risks of general and reproductive health problems following pregnancy.

Currently, data about the link between SMM during the first birth and the odds of subsequent births is lacking. Therefore, investigators conducted a population-based retrospective cohort study to quantify this association.

The Swedish Medical Birth Register (MBR) was cross-linked with the nationwide National Patient Register (NPR) for data about births in Sweden from 2019 to 2021. Data about antenatal, obstetric, and neonatal care was obtained from the MBR while data about inpatient care was obtained from the NPR.

Diagnoses were based on International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes. Women with a first birth during the study period were included, with exclusion criteria including hysterectomy during first birth, missing gestational age or sex, and missing maternal age.

Any SMM between 22 weeks’ gestation and 42 days post-delivery was reported as the primary exposure. SMM was defined with 14 distinct types, based on a validated definition of SMM used for maternal health surveillance in Sweden.

Subsequent birth was reported as the primary outcome, determined using records in the MBR between 1999 and 2021. For stillbirths, data from week 28 of gestation onward was available to July 1, 2008, then from 22 weeks’ gestation afterward. Relevant maternal characteristics were obtained from the MBR.

There were 1,046,974 women included in the final analysis, 3.5% of whom presented with SMM during their initial delivery. These patients were often older, shorter, and more likely to have higher body mass index, pregestational hypertension and diabetes, and assisted reproductive technology use vs those without SMM.

The rate of subsequent births was significantly decreased in women with SMM vs those without SMM, at 136.6 per 1000 person-years vs 182.4 per 1000 person-years, respectively. An adjusted hazard ratio (aHR) for subsequent birth of 0.88 was reported following adjustment for maternal characteristics.

This association was found regardless of SMM type. However, a more significant decrease in the odds of a subsequent birth was reported for cardiac complication, severe uterine rupture, and severe mental health condition, with aHRs of 0.49, 0.48, and 0.48, respectively.

These results indicated reduced odds of undergoing subsequent delivery among women with SMM during their first pregnancy. Investigators recommended adequate reproductive counseling and improved monitoring among women with an SMM.

“The clinical monitoring of these women is essential, and they need individualized advice on possible future pregnancies,” said Eleni Tsamantioti, doctoral student at Karolinska Institutet and first study author.² A steady decline in birth rates has been observed in Sweden over time, highlighting the importance of addressing reproductive health.

References

1. Tsamantioti E, Sandström A, Lindblad Wollmann C, Snowden JM, Razaz N. Association of severe maternal morbidity with subsequent birth. JAMA. 2024. doi:10.1001/jama.2024.20957
2. Women who suffer pregnancy complications have fewer children. Karolinska Institutet. November 25, 2024. Accessed November 25, 2024. https://www.eurekalert.org/news-releases/1065748