Peri-implantation Abstinence and Placental Health

NCT07843173 | Completed DMC

• 1 other identifier: USM/JEPeM/21030234
• Study Type: interventional
• Target: 94
• Locations: 1 country
• Sites: 1

Brief Summary

This study examined whether avoiding sexual intercourse during the time when a fertilized egg may attach to the uterus affects placental development and pregnancy outcomes. Couples who were trying to conceive naturally were assigned by chance to one of two groups. Couples in the abstinence group were asked to avoid sexual intercourse for 14 days after ovulation. Couples in the no-restriction group continued their usual sexual activity without a study-imposed restriction. Participants were followed to determine whether pregnancy occurred and, when applicable, through pregnancy and delivery. During pregnancy, ultrasound was used to assess blood flow between the pregnant participant, placenta, and fetus. After delivery, available placentas were examined for tissue changes, blood-vessel development, and markers of oxidative stress, which reflects the balance between potentially damaging oxidants and the body's antioxidant defenses. Pregnancy and birth outcomes were also recorded. The study was designed to improve understanding of whether sexual activity around the time of implantation may be associated with placental development and pregnancy outcomes.

Conditions

Placental Development Pregnancy Outcome

Keywords

Sexual intercourse; Peri-implantation period Sexual abstinence; Placenta; Placental Development; Placental angiogenesis; Placentation; Natural conception; Placental oxidative stress; Placental histopathology

Outcome Measures

Primary Outcomes (5)

• Placental Malondialdehyde Concentration

  Malondialdehyde concentration was measured in placental tissue as an indicator of lipid peroxidation and normalized to total placental protein. The outcome was reported in nanomoles per milligram of protein.

  At delivery

• Placental Villous Microvessel Density Assessed by CD31 Immunohistochemistry

  Placental villous microvessel density was measured as the mean number of CD31-positive microvessels per high-power field in placental tissue collected after delivery. CD31-positive structures were quantified using a prespecified QuPath-assisted digital image-analysis procedure by assessors blinded to study allocation.

  At delivery

• Placental Superoxide Dismutase Activity

  Superoxide dismutase activity was measured in placental tissue as an indicator of enzymatic antioxidant activity and normalized to total placental protein. The outcome was reported in units per milligram of protein.

  At delivery

• Placental Catalase Activity

  Catalase activity was measured in placental tissue as an indicator of enzymatic antioxidant activity and normalized to total placental protein. The outcome was reported in units per milligram of protein. .

  At delivery

• Placental Total Antioxidant Capacity

  Total antioxidant capacity was measured in placental tissue and normalized to total placental protein. The outcome was reported in micromoles per milligram of protein

  At delivery

Study Arms (1)

Abstinence

EXPERIMENTAL

Couples assigned to this arm were instructed to avoid sexual intercourse for 14 days after ovulation during each study cycle. The abstinence period covered the expected peri-implantation window.

Behavioral: Couples were instructed to avoid sexual intercourse for 14 days after ovulation during each study cycle, covering the expected peri-implantation period.

Interventions

Couples were instructed to avoid sexual intercourse for 14 days after ovulation during each study cycle, covering the expected peri-implantation period. BEHAVIORAL

Couples assigned to the intervention were instructed to avoid vaginal sexual intercourse for 14 consecutive days after ovulation during each study cycle. Ovulation timing was identified using the method specified in the study protocol. The restriction covered the expected peri-implantation period. After the 14-day abstinence period, no further study-imposed restriction on sexual activity was applied

Abstinence

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Women attempting to conceive naturally were eligible as the primary study participants. Participation required a male partner because the intervention involved vaginal sexual intercourse and couple-level abstinence during the peri-implantation period.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Women aged 20 to 40 years
• Attempting to conceive naturally
• Regular menstrual cycles of 28 to 30 days
• No history of major medical or gynecological disorders
• Willingness of both partners to provide written informed consent and follow the assigned study procedures

You may not qualify if:

• Polycystic ovary syndrome
• Endometriosis
• Current or previous tobacco use
• Current or previous alcohol use
• Body mass index below 18.5 or above 30 kg/m²
• Cardiovascular disease
• Chronic hypertension
• Chronic respiratory disease
• Chronic renal disease
• Diabetes mellitus
• Previous pre-eclampsia
• Previous lower-segment cesarean section
• Previous dilatation and curettage
• Previous myomectomy

Sponsors & Collaborators

• Universiti Sains Malaysia: lead

Study Sites (1)

Hospital USM

Kota Bharu, Kelantan, 16150, Malaysia

Location

MeSH Terms

Conditions

Coitus

Condition Hierarchy (Ancestors)

Sexual Behavior; Behavior

Study Officials

• Nik Ahmad Zuky Nik Lah, Prof Obstetrics and gynecology

  Universiti Sains Malaysia

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Postgraduate Researcher, Department of Obstetrics and Gynaecology

Study Record Dates

• First Submitted: September 10, 2026
• First Posted: September 25, 2026
• Study Start: October 1, 2021
• Primary Completion: October 10, 2025
• Study Completion: October 10, 2025
• Last Updated: September 25, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

MY (1)