Increased preterm birth risk not found in endometriosis patients

Increased preterm birth risk not found in endometriosis patients | Image Credit: © Rattanachat - © Rattanachat - stock.adobe.com.

The risks of postpartum hemorrhage and newborn admission to the neonatal unit, but not preterm birth, are increased by endometriosis, according to a recent study published in Fertility and Sterility.¹

Approximately 6% to 10% of reproductive-aged women are impacted by endometriosis, with a rate of 5% reported during pregnancy. Data has indicated increased risks of adverse obstetric and neonatal outcomes among pregnancies with endometriosis, but there is no consensus toward specialist care in these patients.

Preterm birth is reported in 7.4% of live births and is the most significant determinant of adverse neonatal outcomes. It is also the leading cause of perinatal death and disability.² This indicates a significant need to determine preterm birth and other obstetric risks among women with endometriosis during pregnancy.¹

To evaluate obstetric and neonatal outcomes in pregnant women with endometriosis, investigators conducted a single-center, prospective cohort study. Participants included women presenting at the University College London Hospital from October 2017 to November 2019 with a live pregnancy beyond 12 weeks’ gestation.

Women were categorized based on their endometriosis status. Participants received a detailed pelvic ultrasound examination to determine uterine abnormalities alongside endometriosis. Adenomyosis was determined by the presence of at least 1 direct sign or several indirect signs described by the Morphological Uterus Sonographic Assessment group.

Demographic data and medical history were also reported, including age, ethnicity, body mass index, smoking status, gravidity, and parity. Relevant obstetric characteristics included prior endometriosis diagnosis, cesarean section (CS) delivery, early miscarriage, recurrent miscarriage, late miscarriage, preterm birth, ectopic pregnancy, and pelvic surgery.

Preterm birth was reported as the primary outcome, with secondary outcomes including antepartum hemorrhage, placental site disorders, late miscarriage, hypertensive disorders of pregnancy, gestational diabetes mellitus, mode of delivery, neonates small for gestational age (SGA), postpartum hemorrhage, intrapartum sepsis, and neonatal unit admission.

There were 503 women included in the analysis, 21.9% of whom were diagnosed with endometriosis. Of women with endometriosis, the diagnosis was new in 23.6%. Endometriosis alone was reported in 22.7%, deep nodules alone in 38.2%, and both in 30%. Prior surgical excursion of endometriosis was reported in 9.1%.

Women with endometriosis were more often older, nulliparous, conceived after in vitro fertilization, and had undergone pelvic surgery. Similar body mass index, smoking status, and ethnicity were reported in women with and without endometriosis.

There were also no differences in prior CS delivery, multiple pregnancies, late miscarriage, recurrent pregnancy loss, ectopic pregnancy, or preterm delivery between groups. However, women with endometriosis had significantly increased rates of concomitant uterine abnormality vs those without endometriosis, at 27.3% and 13.5%, respectively.

The endometriosis group had a median gestation at delivery of 39 + 1 weeks, vs 39 + 4 weeks in the non-endometriosis group. This indicated a non-significant increase of preterm birth rates among patients with endometriosis, which remained when adjusting for covariates.

No cases of extremely preterm birth were reported, but infants born to women with endometriosis were significantly more likely to be admitted into the neonatal unit, with an adjusted odds ratio (aOR) of 3.24. This association was found regardless of the mode of delivery.

Late miscarriage, placenta previa, placenta accreta, antepartum hemorrhage, gestational diabetes mellitus, intrapartum sepsis, and SGA rates also did not significantly differ between groups. However, postpartum hemorrhage risk during CS was increased among women with endometriosis, with an aOR of 3.64.

These results indicated no increased risk of preterm delivery among women with endometriosis. Investigators concluded increased antenatal care is not necessary in these patients.

References

1. Bean EMR, Knez J, Thanatsis N. Obstetric outcomes in women with pelvic endometriosis: a prospective cohort study. Fertility and Sterility. 2024;122(4):696-705.
2. Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet. 2008;371:261-269