Introduction

Threatened miscarriage is a common pregnancy complication with vaginal bleeding. Progesterone can be used to prevent miscarriage, but it may affect a common screening test evaluating nuchal translucency (NT) for foetal abnormalities. This study investigated the effect of dydrogesterone on the test's accuracy.

Aim

To evaluate the effects of dydrogesterone treatment on first-trimester aneuploidy screening markers and nuchal translucency (NT) in women with threatened miscarriage.

Patient Profile

N=107 pregnant women aged 18-39 years who applied for first-trimester screening test at 11-14th weeks of gestation and confirmed crown-rump length (CRL) of 45 mm to 84 mm in ultrasonographic evaluation.

Methods

• Prospective observational case-control study
• Study group: n= 53 pregnant women using oral dydrogesterone (for atleast 2 weeks) due to the threat of miscarriage and without vaginal bleeding for the last 72 h at the time of enrolment. Dydrogesterone dosage: Daily use of 10 mg orally every 8 h up to 30 mg
• Control group: n=54 healthy pregnant women who did not take exogenous dydrogesterone and without bleeding

Study endpoints

Measurement of foetal CRL, NT, pregnancy-associated plasma protein-A (PAPP-A) level, and free beta-human chorionic gonadotropin (free B-hCG) levels

Results

• No significant differences found in NT Multiple of the Median (MoM) levels, maternal serum PAPP-A, and free B-hCG MoM levels between the study and control groups

  Table 1: Measurements of screening tests and NT in study groups

  	Control Group Mean ± SD	Control Group Median (IQR)	Study Group Mean ± SD	Study Group Median (IQR)	p- value
  Free B-hCG MoM	0.9±0.5	0.81 (0.54-1.11)	0.83±0.39	0.76 (0.55-1.1)	0.654
  PAPP-A MoM	1.04±0.66	0.88 (0.62-1.34)	0.99±0.78	0.74 (0.61-1.08)	0.299
  NT MoM	0.91±0.22	0.92 (0.79-1.02)	0.95±0.17	0.93 (0.83-1.04)	0.241

   

• In four subgroups created according to CRL measurements, no significant differences found in NT levels, maternal serum PAPP-A, and free B-hCG levels
• No significant relationship found between maternal, foetal parameters and NT MoM values. A negative significant relationship was found between NT MoM and CRL mm only in drug users and non-users (p<0.05). As CRL measurements increased, regardless of drug use, the NT MoM value decreased

Conclusion

• Use of dydrogesterone in first-trimester pregnancies does not affect first-trimester screening tests and nuchal translucency
• Oral dydrogesterone is easier to take than other progesterone medications and doesn't interfere with the test. If these findings are supported by studies involving larger numbers of participants, dydrogesterone can be potentially better option for pregnant women

Reference

Turk J Obstet Gynecol 2023;20:16-21