This randomized controlled trial aims to compare the efficacy of Dydrogesterone alone versus Dydrogesterone combined with human chorionic gonadotrophin (HCG) in the treatment of threatened miscarriage in first trimester pregnancy.

Threatened miscarriage is defined as vaginal bleeding with abdominal or pelvic pain in early pregnancy with a closed cervical os. It is one of the most common complications of pregnancy and may lead to pregnancy loss if not managed appropriately.

In this study, eligible women aged 18-40 years presenting with threatened miscarriage will be randomly assigned into two groups. Group A will receive oral Dydrogesterone 10 mg twice daily, while Group B will receive oral Dydrogesterone 10 mg twice daily along with intramuscular human chorionic gonadotrophin (HCG) 5000 IU weekly up to 14 weeks of gestation.

The primary outcome is treatment efficacy, defined as absence of vaginal bleeding and pain score ≤4 on Visual Analogue Scale (VAS) after 14 days of treatment.

The results of this study will help determine whether the addition of HCG to Dydrogesterone provides superior clinical benefit in threatened miscarriage and may guide future treatment protocols.

Threatened miscarriage is a common complication in early pregnancy, affecting a significant proportion of women in the first trimester. It is clinically defined by vaginal bleeding with or without abdominal pain while the cervical os remains closed. Although many pregnancies with early bleeding continue successfully, a considerable proportion may progress to miscarriage, making early and effective management essential.

Progesterone plays a key role in the maintenance of pregnancy by supporting endometrial stability and preventing uterine contractions. Dydrogesterone, a synthetic progesterone, is widely used for the management of threatened miscarriage. However, clinical outcomes remain variable, and additional therapeutic strategies are being explored.

Human chorionic gonadotrophin (HCG) is a glycoprotein hormone produced by the syncytiotrophoblast early in pregnancy. It supports corpus luteum function and progesterone production and may also have direct effects on uterine blood flow, angiogenesis, and endometrial receptivity. These mechanisms suggest a potential benefit of combining HCG with progesterone therapy.

This randomized controlled trial will be conducted in the Department of Obstetrics and Gynecology, PAF Hospital Islamabad after approval from the ethical review committee. A total of 100 women diagnosed with threatened miscarriage in the first trimester will be enrolled through consecutive non-probability sampling and randomly assigned into two equal groups.

Group A will receive oral Dydrogesterone 10 mg twice daily, while Group B will receive the same dose of Dydrogesterone along with intramuscular HCG 5000 IU weekly until 14 weeks of gestation.

Participants will be followed for 14 days after initiation of treatment. The primary outcome measure is treatment efficacy, defined as absence of vaginal bleeding and pain score ≤4 on Visual Analogue Scale (VAS). Secondary analysis will include comparison of efficacy between both groups using chi-square test, with p-value <0.05 considered statistically significant.

Data will be analyzed using SPSS version 24. Results of this study will provide evidence regarding the comparative effectiveness of combination therapy versus progesterone alone in the management of threatened miscarriage and may contribute to improved clinical guidelines in local population settings.

Inclusion Criteria:

• Women with singleton pregnancy diagnosed as threatened miscarriage in the first trimester
• Age 18 to 40 years
• Presence of vaginal bleeding with or without abdominal pain and closed cervical os
• Viable pregnancy confirmed on ultrasound (fetal cardiac activity present)
• Willing to provide written informed consent

Exclusion Criteria:

• History of oxytocin or prostaglandin use during current pregnancy
• History of abdominal trauma during pregnancy
• Septic abortion or signs of infection
• Hemodynamically unstable patients
• Known bleeding disorders
• Known uterine anomalies
• Failed or inevitable miscarriage at presentation

The plan for sharing individual participant data (IPD) is currently undecided. Data sharing decisions will be made after completion of the study, taking into account institutional policies, ethical committee guidelines, and publication requirements. Any future data sharing will ensure participant confidentiality and compliance with relevant regulations.

No blinding will be applied in this study. Both participants and investigators will be aware of the treatment allocation.