Sexual Intercourse on Spontaneous Onset of Labor

Participants comprised pregnant women who were receiving prenatal care at the Maternity and Neonatology Center in Tunis (CMNT). This study was a quasi-experimental, comparative, longitudinal, prospective, and monocentric over one year, from September 24, 2021, to September 24, 2022.

Women in the study had to be aged between 18 and 45 years and had to be with uncomplicated singleton pregnancies with gestational age of 37 weeks and above, at low risk for complication, with intact membranes, and in cephalic presentation. Exclusion criteria were pregestational or gestational hypertension, preeclampsia, gestational diabetes, epilepsy in the mother, type 1 or 2 diabetes, contraindications to vaginal delivery, any type of hospitalization, increased surveillance due to suspicion of preterm labor, unexplained vaginal bleeding, sexually transmitted disease, or fetal anomalies.

The study involved pregnant women who were randomly assigned to two groups. The protocol involved engaging in sexual intercourse and nipple stimulation 3 times per day for two consecutive weeks with the consecutive days of sexual intercourse and days of nipple stimulation being different. Patients documented their coital activities as well as the frequency of orgasms in their daily journal. There were no prohibitions regarding or promotions of sexual activities for the control group. The main outcome was the onset of labor, which was defined as the presence of effective uterine contraction with changes of the cervix (Bishop score > 5) without using the induction treatments during protocol time or until 41 weeks of pregnancy.

The subjects were divided into experimental and control groups using simple random sampling. To eliminate group-bias during the allocation, a computer assigned a sequence of random numbers to all the participants. To eliminate selection bias, allocation concealment was ensured by using sequentially numbered, sealed, opaque envelopes which were prepared by an otherwise unrelated third party. Age and parity were considered for stratification of cases and controls to have relatively equal distribution across the groups.

Quantitative data were obtained from the women through self-administered questionnaires which focused on sexual activity during pregnancy and at term. A chi-square test was carried out to determine if there is a significant relationship between sexual intercourse and the incidence of spontaneous onset of labor. Data analysis was performed using SPSS 21 stats software, with a level of significance set at 0.05.

Both the study aim, and protocol were approved by the ethics committee of the Maternity and Neonatology center of Tunis. Informed consent was obtained from all participants. Participants' anonymity and data confidentiality were upheld throughout the study.

Inclusion criteria

• We included pregnant women (primiparous or multiparous) who presented to the perinatal consultation of the maternity and neonatology center of Tunis. Their pregnancies are evolving singleton, low risk, with intact membranes and cephalic presentation.

Exclusion criteria

• The non-inclusion criteria were high-risk pregnancies:

• pregnancy pathologies: pregnancy-induced hypertension, pre-eclampsia, gestational diabetes, pregnancy-induced cholestasis, IUGR.
• maternal pathologies: epilepsy, type 1 or 2 diabetes.
• contraindications to vaginal delivery: placenta previa or accreta, history of two (or more) cesarean sections, breech or transverse presentation.
• hospitalizations and/or increased monitoring during pregnancy related to a threat of premature delivery, undetermined bleeding, sexually transmitted diseases, fetal pathologies and/or malformations.

Patients who did not follow the protocol for any reason.