Single serum hCG level 16 days after ovulation useful predictor of pregnancy outcome, suggests study
After assisted reproductive technology (ART) cycles, elevated serum hCG at 16 days after ovulation is used as an endocrine marker of pregnancy. Whether the pregnancy is ongoing is uncertain at this stage. Diagnosis of pregnancy has both emotional and practical implications for the pregnant woman, her family, and health care practitioners. Early diagnosis with knowledge of prognostic outcome has the potential to reduce the stress often associated with the uncertainty of outcome in ART treatment. The pregnancy test under evaluation was obtained from a single blood test taken 16 days after ovulation, which is assayed for levels of hCG and progesterone. Human chorionic gonadotropin is secreted from the implanting blastocyst and appears in maternal blood approximately 6–8 days after fertilization.
It would be beneficial for the patient, her family, and the clinical team to have a reliable prognostic marker of pregnancy outcome at this early stage. For the patient, ART treatment is often stressful, and waiting for pregnancy test results can be a time of tension and uncertainty. Information provided by staff to patients may be inconsistent or nonspecific, causing further stress and uncertainty.
The objective of this retrospective study study by Gillian Homan was to assess the predictive value on pregnancy outcome based on serum hCG and progesterone levels 16 days after ovulation. Other factors, such as treatment method, ovarian stimulation, luteal support, and age, were also included in the analysis.
The data were obtained from two integrated Adelaide-based clinics: the Queen Elizabeth Hospital and Wakefield Clinic. Patient(s): Women who have achieved a pregnancy through ART treatment. Analysis of data using logistic regression (STATA v.5.0) to predict a binary outcome: ongoing pregnancy or miscarriage. Ongoing pregnancy was defined as progression to >20 weeks’ gestation. Miscarriage included spontaneous abortion, biochemical and ectopic pregnancies, and blighted ovum.
Human chorionic gonadotropin was found to be the main determinant of ongoing pregnancy. Age and progesterone had minor effects, whereas stimulation, luteal support, and treatment types were nonpredictive. Low hCG levels between 25 and 50 IU/L are associated with a low probability of ongoing pregnancy (<35%), whereas levels of >500 IU/L predict a >95% chance of ongoing pregnancy.
This study confirms the hypothesis that serum levels of hCG in samples taken 16 days after ovulation are powerful predictors of good or poor pregnancy outcome. Because of the large sample size, statistical modeling could predict with precision, on the basis of the hCG level alone, the probability of ongoing pregnancy. The strength of the relationship was sufficient to allow its use at a clinical level for the prediction of pregnancy outcome to the exclusion of all other markers.
In conclusion, a single serum sample taken and assayed 16 days after ovulation, following ART treatment, is clinically useful in predicting pregnancy outcome. This is valuable information for both patients and practitioners, because it does reduce anxiety and provide a basis for early pregnancy management and monitoring. The findings of this study could be included in a patient information sheet, because the relationship between the level of hCG, age, and the predictive value of pregnancy outcome is comprehensible to patients. This study included all ART treatment cycles; therefore, this information can be used for all patients in units where a variety of ART procedures are practiced.
Source: Gillian Homan, B.N., Susan Brown, R.N., John Moran; FERTILITY AND STERILITY
