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Completed

NCT Number: NCT07843173

Peri-implantation Abstinence and Placental Health

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.

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Key information

Conditions

Placental Development Pregnancy Outcome Behavior Coitus Sexual Behavior

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Hospital USM

Kota Bharu, Kelantan, 16150, Malaysia

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Treatment and study plan

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

Primary outcomes

  1. Placental Malondialdehyde Concentration

    Time frame: At delivery

    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.

  2. Placental Villous Microvessel Density Assessed by CD31 Immunohistochemistry

    Time frame: At delivery

    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.

  3. Placental Superoxide Dismutase Activity

    Time frame: At delivery

    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.

  4. Placental Catalase Activity

    Time frame: At delivery

    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.

    .

  5. Placental Total Antioxidant Capacity

    Time frame: At delivery

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

Interested in participating?

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Sponsors and collaborators

Lead sponsor

Universiti Sains Malaysia

Other

Registry information

Official study title

Effects of Peri-Implantation Sexual Abstinence on Placentation and Its Outcomes

Important dates

Study start
2021
Primary completion
2025
Study completion
2025
First posted
Sep 25, 2026
Registry last updated
Sep 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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