OBGYN practice patterns regarding combination therapy for prevention of preterm birth: A national survey

Our objective was to examine if US obstetrician-gynecologists (OBGYNs) practice outside of evidenced-based guidelines and use a combination of interventions to prevent spontaneous preterm birth (sPTB).

An electronic survey was distributed to members of the Pregnancy-Related Care Research Network (PRCRN), and also to members of the Society of Maternal-Fetal Medicine (SMFM). The survey consisted of questions regarding physician demographics, and the use of interventions to prevent sPTB in women with 1) a prior sPTB, 2) an incidental short cervix (no prior sPTB), and 3) a history of cervical insufficiency.

The PRCRN response rate was 58.6% (283/483) with an additional 143 responses from SMFM members. Among PRCRN responders, 82.7% were general OBGYNs and 17.3% were Maternal-Fetal Medicine subspecialists. Respondents were from all geographic regions of the country; most practiced in a group private practice (42.6%) or academic institution (31.4%). In women with prior sPTB, 45.2% of respondents would consider combination therapy, most commonly weekly intramuscular progesterone (IM-P) and serial cervical length (CL) measurements. If the patient then develops a short cervix, 33.7% would consider adding an ultrasound-indicated cerclage. In women with an incidental short cervix, 66.8% of respondents were likely to recommend single therapy with daily vaginal progesterone (VP). If a patient developed an incidentally dilated cervix, 40.8% of PRCRN respondents would recommend dual therapy, most commonly cerclage + VP, whereas 64.3% of SMFM respondents were likely to continue with VP only. In women with a history of cervical insufficiency, 47% of PRCRN respondents indicated they would consider a combination of IM-P, history-indicated cerclage and serial CL measurements.

Although not currently supported by evidence-based medicine, combination therapy is commonly being used by U.S. OBGYNs to prevent sPTB in women with risk factors such as prior sPTB, short or dilated cervix or more than one of these risks.