Introduction:
Prenatal diagnostic testing allows for early identification of clinically actionable conditions of the fetus. However, patients with pregnancies complicated by fetal anomalies often do not undergo diagnostic genetic testing until the postpartum period. This work aims to identify factors associated with the timing of diagnostic testing in pregnancies with known fetal anomalies.

 

Methods:
We retrospectively analyzed outcomes for pregnancies with fetal anomalies who were referred for genetic counseling at a large tertiary care hospital system between 1/2021 and 12/2023. The primary outcome measures were the rates of diagnostic testing (prenatal only, postnatal only, both prenatal and postnatal) and the associated fetal anomalies. Pregnancies with multiple gestation and anomalies due to infection were excluded. Non-parametric statistical methods were used.

 

Results:
A total of 1170 pregnancies were reviewed with 662 (56.6%) identified as having diagnostic genetic testing. Of these, 177 (26.7%) underwent prenatal testing alone, 414 (62.5%) underwent postnatal testing alone, and 71 (10.7%) underwent both.  The gestational ages at referral were 21 weeks, 30 weeks, 23 weeks, and 25 weeks for prenatal only, postnatal only, both, and no testing, respectively (p=<0.01). Prenatal testing alone was more common among pregnancies with neural tube defects (28.2% vs 1.2%, 1.4%, 4.1% for postnatal alone, both, and none, p=<0.01) while postnatal testing alone was more common among pregnancies with cardiac anomalies (54.6% vs 23.2%, 31.0%, 24.2% prenatal alone, both, and none, p=<0.01). Pregnancies with congenital diaphragmatic hernias commonly had both prenatal and postnatal testing (26.8% vs 9.6%, 5.1%, and 1.4% for prenatal alone, postnatal alone, and no testing, p=<0.01). Pregnancies with renal anomalies were more likely to have no testing at all (17.9% vs 1.1%, 1.9%, 0.0% for prenatal alone, postnatal alone, and both, p=<0.01). Pregnancies that underwent prenatal genetic testing were more likely to have a primary cesarean delivery (48.6% vs 28.0%, 38.0%, 28.3%, p=0.039), but there was no association with nulliparity (p=0.888).

 

Conclusion:
Our findings indicate that prenatal diagnostic testing rates exhibit variability depending on the type of anomaly, yet prenatal diagnostic testing may be associated with primary cesarean delivery. The implications of prenatal diagnostic testing for women with genetic disorders are profound, particularly in the context of reproductive planning. Further research is needed to identify and address the barriers to diagnostic testing within this population.