Natural evolution of the ovarian hyperstimulation syndrome (OHSS)

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 04/25/2014

The OHSS is a self-limited alteration, since it may disappear at the beginning of your menstrual period. In such cases, the Ovarian Hyperstimulation Syndrome lasts 10-14 days.

The clinical resolution of OHSS occurs as hCG diminishes. hCG (human chorionic gonadotropin) is an hormone used to detect if a woman is pregnant. This hormone's synthesis occurs within the brain of both men and women with different purposes:

  • Men: it is involved in the production of testosterone in the testes.
  • Women: it induces egg maturity.

In addition, hCG is also produced within a part of the placenta (syncytiotrophoblast) and the embryo; hence the increase of its levels in pregnant women.

Ovarian hyperstimulation syndrome

During pregnancy, hCG prevents the disintegration of the corpus luteum in the ovary and maintains the production of progesterone, the latter being extremely important during pregnancy. Furthermore, it is involved in the immune tolerant phase of pregnancy.

Since hCG secretion starts 6 days after you get pregnant, it can be used as a marker of pregnancy. This is the reason why, if pregnancy has occurred, the OHSS can be extended, which may worsen the patient's clinical picture. Late OHSS may last 60-70 days.

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 Neus Ferrando Gilabert
Neus Ferrando Gilabert
BSc, MSc
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information about Neus Ferrando Gilabert
Adapted into english by:
 Sandra Fernández
Sandra Fernández
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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