In vitro fertilization as an independent risk factor for placenta accreta spectrum

Abstract

BACKGROUND: Placenta accreta spectrum is well known for its association with catastrophic maternal outcomes. However, its pathophysiology is not well defined. There have been emerging data that in vitro fertilization may be a risk factor for placenta accreta spectrum. OBJECTIVE: We investigated the hypothesis that in vitro fertilization is an independent risk factor for placenta accreta spectrum. STUDY DESIGN: A retrospective analysis of all deliveries in a prospective, population-based cohort (2012e2019) was performed in a tertiary academic center. Primary outcome variable was placenta accreta spectrum. Univariate analysis was performed on potential risk factors for predicting placenta accreta spectrum, and a multivariate model was designed to best fit the prediction of placenta accreta spectrum adjusted for risk factors such as cesarean delivery, placenta previa, age, and parity. History of previous cesarean delivery was known as a risk factor for both placenta previa and placenta accreta spectrum; hence, the interaction between "placenta previa" and "previous cesarean delivery" was included in the final model. Odds ratios were calculated as exponential of beta coefficients from the multivariate regression analysis. RESULTS: A total of 37,461 deliveries were included in this analysis, 5464 (15%) of which had a history of cesarean delivery, 281 (0.7%) had placenta previa in their index pregnancy, and 571 (1.5%) had in vitro fertilization pregnancy. The frequency of placenta accreta spectrum was 230 (0.6%). Independent risk factors for placenta accreta spectrum were in vitro fertilization pregnancy (adjusted odds ratio, 8.7; 95% confidence interval, 3.8e20.3), history of previous cesarean delivery (adjusted odds ratio, 21.1; 95% confidence interval, 11.4e39.2), and presence of placenta previa (adjusted odds ratio, 94.6; 95% confidence interval, 29.3e305.1). After adjustment for number of previous cesarean deliveries, the correlation persisted for in vitro fertilization (adjusted odds ratio, 6.7; 95% confidence interval, 2.9e15.6). CONCLUSION: Our data suggested that in vitro fertilization is an independent risk factor for placenta accreta spectrum, although its relative clinical importance compared with that of the presence of placenta previa and history of cesarean delivery is small. The pathophysiology behind this relationship remains to be investigated.

<p>Placenta Accreta Spectrum Disorders: Challenges, Risks, and Management Strategies</p>

“…Alternatively, lower serum estradiol levels together with the presence of a thinner decidualized endometrium may result in abnormal trophoblastic growth leading to PAS. 15 In normal placentation, extravillous trophoblast cells undertake a remodeling process of uterine arteries leading to the progressive loss of myocytes and their internal elastic lamina, which are replaced by fibrinoid material. Consequently, the terminal coils of the spiral arteries are dilated by an approximately 4-fold increase in their diameter at the myometrial-endometrial interface and within the distal myometrium.…”

“…27,28 Additional risk factors are advanced maternal age, high parity, IVF, and a diagnoses of PAS in a previous pregnancy. 14,15,29,30 However, the major risk factor for PAS is a prior cesarean delivery in combination with placenta previa, namely, a placenta implanting over the cervical os. Moreover, the risk of PAS increases progressively with increasing number of previous cesarean deliveries.…”

“…Alternatively, lower serum estradiol levels together with the presence of a thinner decidualized endometrium may result in abnormal trophoblastic growth leading to PAS. 15 …”

“… 27 , 28 Additional risk factors are advanced maternal age, high parity, IVF, and a diagnoses of PAS in a previous pregnancy. 14 , 15 , 29 , 30 …”

Placenta Accreta Spectrum

“…Past uterine surgeries such as curettage, myomectomy, ablation, and surgical abortion are linked to increased incidence of PAS because of instrumental disruption of the endometrium 2,3 . In vitro fertilization, particularly those with cryopreserved embryo transfer cycles, has been identified as an independent risk factor for PAS, although the pathophysiology is not yet well understood 15 . Additional risk factors for PAS include advanced maternal age, smoking, multiparity, endometriosis, manual removal of the placenta, uterine abnormalities, and short pregnancy intervals after cesarean birth 5,16 …”