Use of serum progesterone measurements to reduce need for follow‐up in women with pregnancies of unknown location

Objective To assess the efficacy of a progesterone-based algorithm for the management of women with pregnancies of unknown location (PULs) and explore the feasibility of developing a single-visit strategy in those with a low risk of requiring medical intervention. Methods All clinically stable women in whom pregnancy could not be identified on ultrasound scan were managed by a pre-defined protocol based on measurement of serum progesterone and β-human chorionic gonadotropin (β-hCG). Intervention in the form of surgery or medical treatment with methotrexate was offered to all women with persistent or worsening symptoms and non-declining serum β-hCG. Decision-tree analysis was used to develop a protocol for the management of women with resolving pregnancies who are at low risk of requiring medical intervention. Results 1110 women were included in the data analysis: normal intrauterine pregnancy was diagnosed in 248 (22.3%; 95% CI, 19.9–24.8) women. 761 (68.6%; 95% CI, 65.8–71.3) abnormal pregnancies resolved spontaneously on expectant management, while the remaining 101 (9.1%; 95% CI, 7.4–10.8) women with abnormal pregnancies required some form of medical intervention. Intervention rates in patients presenting with initial serum progesterone levels of ≤ 20 nmol/L and ≤ 10 nmol/L, were 3.9% (95% CI, 2.4–5.4) and 2.1% (95% CI, 0.9–3.3), respectively. In women presenting with progesterone ≤ 10 nmol/L and β-hCG < 450 IU/L, the intervention rate was 1.3% (95% CI, 0.2–2.5). Conclusion Women with PULs with progesterone ≤ 10 nmol/L at presentation are at low risk of requiring medical intervention and may not benefit from attending routine follow-up visits. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.