Maternal implications of fetal anomalies: a population-based cross-sectional study

Although it is well-known that the presence of fetal anomalies is associated with maternal morbidity, granular information on these risks by type of anomaly is not available.

To examine adverse maternal outcomes according to the type of fetal anomaly.

This was a repeated cross-sectional analysis of US vital statistics Live Birth/Infant Death linked data from 2011 to 2020. All pregnancies at 20 weeks or greater were included. Our primary outcome was severe maternal morbidity (SMM), defined as any maternal intensive care unit admission, transfusion, uterine rupture, or hysterectomy. Outcomes were compared between pregnancies with a specific type of fetal anomaly and pregnancies without any fetal anomaly. Fetal anomalies that were available in the dataset included anencephaly, meningomyelocele/spina bifida, cyanotic congenital heart disease, congenital diaphragmatic hernia, omphalocele, gastroschisis, cleft lip and/or palate, hypospadias, limb anomaly, and chromosomal disorders. If a fetus had more than one anomaly, it was classified as multiple anomalies. Adjusted relative risks (aRR) with 99% confidence intervals (99% CI) were calculated using modified Poisson regression. Adjusted risk differences (aRDs) were calculated using the marginal standardization form of predictive margins.

Of 35,760,626 pregnancies included in the analysis, 35,655,624 pregnancies had no fetal anomaly and 105,002 had isolated or multiple fetal anomalies. Compared to pregnancies without fetal anomaly, all fetal anomalies were associated with an increased risk of SMM except for gastroschisis and limb anomaly in order of aRRs (99% CI): 1.58 (1.29-1.92) with cleft lip and/or palate; 1.75 (1.35-2.27) with multiple anomalies; 1.76 (1.18-2.63) with a chromosomal disorder; 2.19 (1.82-2.63) with hypospadias; 2.20 (1.51-3.21) with spina bifida; 2.39 (1.62-3.53) with congenital diaphragmatic hernia; 2.66 (2.27-3.13) with congenital heart disease; 3.15 (2.08-4.76) with omphalocele; and 3.27 (2.22-4.80) with anencephaly. Compared to pregnancies without fetal anomaly, all fetal anomalies were associated with an increased absolute risk of SMM except for gastroschisis and limb anomaly in order of aRDs (99% CI): 0.26 (0.12-0.40) with cleft lip and/or palate, 0.34 (0.13-0.55) with multiple anomalies, 0.34 (0.02-0.66) with a chromosomal disorder, 0.54 (0.36-0.72) with hypospadias, 0.54 (0.17-0.92) with spina bifida, 0.63 (0.21-1.05) with congenital diaphragmatic hernia, 0.75 (0.56-0.95) with congenital heart disease, 0.97 (0.38-1.56) with omphalocele, and 1.03 (0.46-1.59) with anencephaly.

The presence of fetal anomalies is associated with adverse maternal health outcomes. The risk of SMM varies according to the type of fetal anomaly. Counseling mothers about the maternal implications of fetal anomalies is paramount to help them make informed decisions regarding their pregnancy outcome.