Obstetrics: Original Research Association Between First-Trimester Subchorionic Hematomas and Pregnancy 07/11/2019 on UX4fYMCnOcHFIEHDrKGaxtsRmgMN6+Y9eLjOHopED2iuKWe9f7f10tNtfYFKNN8oMqHumdSLrWfAO1hz3KsgtaKT3ioHIBOioLj2BOC7gV9SpegpqCWRgKyU9rzcZR/p by https://journals.lww.com/greenjournal from Downloaded Loss in Singleton Pregnancies Downloaded Mackenzie N. Naert, BA, Hanaa Khadraoui, BA, Alberto Muniz Rodriguez, BA, Mariam Naqvi, MD, from and Nathan S. Fox, MD https://journals.lww.com/greenjournal OBJECTIVE: To assess the association of a first-trimester bleeding, this association was no longer significant subchorionic hematoma with pregnancy loss in women (adjusted odds ratio 1.13, 95% CI 0.74–1.74). In the 451 with singleton pregnancies. women with subchorionic hematomas, no characteristics of the subchorionic hematoma, including size by volume, by METHODS: We conducted a retrospective cohort study UX4fYMCnOcHFIEHDrKGaxtsRmgMN6+Y9eLjOHopED2iuKWe9f7f10tNtfYFKNN8oMqHumdSLrWfAO1hz3KsgtaKT3ioHIBOioLj2BOC7gV9SpegpqCWRgKyU9rzcZR/p of all women with singleton pregnancies presenting for largest diameter, presence of vaginal bleeding, and pres- prenatal care before 14 weeks of gestation over a 3-year ence of an additional subchorionic hematoma, were period at a single obstetric practice. All patients had associated with pregnancy loss. Post hoc power analysis routine first-trimester ultrasound scans. We reviewed showed we had 80% power to detect an increase in ultrasound data from the first ultrasound scan performed pregnancy loss before 20 weeks of gestation from 4.9% between 6 0/7 and 13 6/7 weeks of gestation and in women with no subchorionic hematoma to 8.3% in compared rates of pregnancy loss before 20 weeks in women with subchorionic hematoma. women with and without a subchorionic hematoma. CONCLUSION: In this cohort of women with singleton Logistic regression analysis was used to control for pregnancies, subchorionic hematoma before 14 weeks of potential confounding variables. gestation was not independently associated with preg- RESULTS: From January 2015 to December 2017, a total nancy loss before 20 weeks of gestation. of 2,446 women met inclusion criteria, 451 (18.4%) of (Obstet Gynecol 2019;00:1–6) whom had subchorionic hematomas. Women with sub- DOI: 10.1097/AOG.0000000000003360 chorionic hematomas had their first ultrasound scans at an earlier gestational age (8 5/7 vs 9 6/7 weeks of ubchorionic hematomas are commonly observed gestation, P,.001) and were more likely to have vaginal Son ultrasound scans during the first trimester, with bleeding (33.3% vs 8.1%, P,.001). Maternal age, race, use reported incidence varying widely, from as low as of in vitro fertilization, body mass index, prior number of 0.46% to as high as 39.5%.1–3 Data are conflicting losses, and medical comorbidities did not differ between regarding the clinical implications of subchorionic the groups. On univariable analysis, subchorionic hema- hematomas. toma was associated with an increased risk of pregnancy One of the most reported adverse associations loss before 20 weeks of gestation (7.5% vs 4.9%, P5.026); with subchorionic hematoma is pregnancy loss. however, after adjusting for gestational age and vaginal Although a large systematic review found that sub- chorionic hematoma was correlated with a twofold From the Icahn School of Medicine at Mount Sinai, New York, Touro College of 4 Osteopathic Medicine, Harlem, and Maternal Fetal Medicine Associates, PLLC, increase in spontaneous abortion, other studies have on New York, New York. found either a lower risk of pregnancy loss5,6 or no 07/11/2019 Each author has confirmed compliance with the journal’s requirements for association between subchorionic hematoma and authorship. pregnancy loss.7,8 Subchorionic hematomas’ timing Corresponding author: Mackenzie N. Naert, BA, New York, NY; email: and size may also affect rates of pregnancy loss.3,9 [email protected]. However, these studies are often limited by lack of Financial Disclosure The authors did not report any potential conflicts of interest. important clinical information and inability to control for important covariates that may influence the preg- © 2019 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved. nancy loss rate. Additionally, in many studies, the ISSN: 0029-7844/19 patients do not represent a general obstetrics VOL. 00, NO. 00, MONTH 2019 OBSTETRICS & GYNECOLOGY 1 © 2019 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. population because study participants may have ences in baseline characteristics between the two received an early ultrasound scan only as a result of groups that were significant in the univariable analysis the use of in vitro fertilization (IVF), recurrent preg- (P,.05). Adjusted odds ratios with 95% CIs were esti- nancy losses, or vaginal bleeding, for example. mated from the regression analysis. For the subgroup Thus, the relationship between subchorionic of women with subchorionic hematomas, we also as- hematoma and pregnancy loss is unclear. The objec- sessed whether the subchorionic hematomas’ largest tive of this study was to investigate the association diameter, volume (length 3 width 3 height), or num- between first-trimester subchorionic hematoma and ber was associated with pregnancy loss. Lastly, we pregnancy loss in unselected women with a range of assessed whether vaginal bleeding increased the risk comorbidities and singleton pregnancies. In addition, of pregnancy loss among women with subchorionic we sought to better understand whether any particular hematomas. ultrasound or clinical features of subchorionic hema- This project was approved by the Biomedical toma are associated with an increased risk of preg- Research Alliance of New York Institutional Review nancy loss to better counsel patients with this Board. There was no funding for this study. common first-trimester diagnosis. METHODS RESULTS This was a retrospective cohort study of all women A total of 2,586 women presented for prenatal care with singleton pregnancies who presented for prenatal before 14 weeks of gestation with singleton gestations care before 14 weeks of gestation at a single maternal– over the course of the study period. We excluded 30 fetal medicine practice over a 3-year period between women for fetal heart rate less than 100 beats January 2015 and December 2017. In our practice, all per minute and 39 women for the presence of women undergo ultrasound scans at our affiliated a vanished twin, leaving 2,517 women eligible for imaging center at or before their initial visits. All inclusion, 468 (18.6%) of whom had a subchorionic images are archived, and formal reports are gener- hematoma. There were a total of 71 women (2.7%) ated. For each patient, we reviewed the initial ultra- without outcome data because they left our practice sound scan performed between 6 0/7 and 13 6/7 before 20 weeks of gestation, and this rate did not weeks of gestation. Gestational age was determined by differ between the subchorionic hematoma and non– the last menstrual period or by first-trimester ultra- subchorionic hematoma groups (3.6% vs 2.6%, sound scan per standard guidelines.10 If the preg- P5.24). Therefore, a total of 2,446 women were nancy was the result of IVF, the date of embryo included in the final analysis, 451 (18.4%) of whom transfer was used to determine gestational age. We had subchorionic hematomas and 1,995 (81.6%) of excluded pregnancies with multiple gestations, a van- whom did not have subchorionic hematomas. ishing twin, or a fetal heart rate of less than 100 beats Women with a subchorionic hematomas pre- per minute. sented at earlier gestational ages and were more likely We reviewed each ultrasound report for the to have vaginal bleeding. There were no differences in presence or absence of a subchorionic hematoma, any other measured baseline characteristics, including the total number of subchorionic hematomas, the size maternal age, race, body mass index (BMI, calculated of any subchorionic hematomas, and the presence or as weight in kilograms divided by height in meters absence of vaginal bleeding, which are all routinely squared), use of IVF, prior pregnancy losses, uterine noted on the ultrasound report. Subchorionic hema- anomalies, leiomyomas, cervical excisional proce- toma was defined as a crescent-shaped, echo-free area dures, prior preterm birth, and medical comorbidities between the chorionic membrane and the myome- (Table 1). trium.2 We also reviewed computerized medical re- On univariable analysis, subchorionic hematoma cords for each woman to obtain demographic and was associated with an increased risk of pregnancy baseline clinical information. loss before 20 weeks of gestation (7.5% vs 4.9%, We compared baseline characteristics between P5.026). However, after adjusting for gestational age the women with and without subchorionic hematomas at ultrasound scan and presence of vaginal bleeding, using x2 and t tests as appropriate. Our primary out- this association was no longer significant (adjusted come was pregnancy loss before 20 weeks of gesta- odds ratio 1.13, 95% CI 0.74–1.74) (Table 2). Post tion, and we compared this outcome between women hoc power analysis showed we had 80% power (alpha with and without subchorionic hematomas. Multivari- error of 5%) to detect an increase in pregnancy loss able logistic regression was