Maternal serum a-fetoprotein in twin pregnancy

Johnson, Jo‐Ann; Harman, C.; Evans, Jackie; MacDonald, Kim; Manning, F. A.

doi:10.1016/0002-9378(90)91308-y

Cited by 27 publications

(15 citation statements)

References 8 publications

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“…However, as suming that each normal fetus produces its own AFP in twin pregnancies, in a large data base the AFP production for each twin should be comparable to 1.0 MOM in a singleton pregnancy of similar gestational age. Thus, the difference between the MSAFP twin to singleton ratio in our study and the one de scribed by Johnson et al [6] can be explained by our larger study group.…”

Section: Commentsmentioning

confidence: 53%

“…We found that the MSAFP in twin gestations is 2.1 times higher than the MSAFP of singletons of com parable gestational age. This twin to singleton median ratio is lower than the 2.5 ratio de-scribed by Johnson et al [6]. However, as suming that each normal fetus produces its own AFP in twin pregnancies, in a large data base the AFP production for each twin should be comparable to 1.0 MOM in a singleton pregnancy of similar gestational age.…”

Section: Commentsmentioning

confidence: 67%

“…Thus, the expected median MSAFP in twins is approxi mately twice the MOM for singletons of the same gestational age. In a study of 136 twin pregnancies, Johnson et al [6] reported a me dian MSAFP for twins that is parallel to the median of singletons but 2.5 times higher. These authors used MSAFP values adjusted for maternal weight and insulin-dependent diabetes, but did not correct for race.…”

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confidence: 99%

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Similarity of Twins to Singleton Maternal Serum Alpha-Fetoprotein Ratio by Race: No Need to Establish Specific Multifetal Tables

et al. 1993

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The purpose of this study was to assess the need for race-specific maternal serum α-fetoprotein (MSAFP) curves in twin gestations. MSAFP values were evaluated in 535 samples obtained from twin gestations. Results were grouped according to gestational age (from 15 to 20 weeks), as with our singletons. Separate median curves were determined for black and for white pregnancies. On average, the median serum α-fetoprotein (AFP) for twins was about twice (2.1 ± 0.3) the median of singletons. MSAFP in blacks was commonly higher than in white pregnancies of comparable gestational age. Using a 4.5 multiple of the singleton median cutoff in twin white pregnancies, 3.9% of the results were defined as ‘high’, similar to the rate observed in singleton pregnancies. ‘Low’ results in twins were defined as AFP values lower than 1.0 multiples of the singleton median (in pregnancies of similar gestational age and race). About 7 % of the serum samples for whites were defined as ‘low’ by this criteria. Data for blacks were comparable. Race-dependent median values should be used for MSAFP interpretation in twin as well as singleton pregnancies. ‘High’ and ‘low’ percentages are comparable to our large data bank of singleton pregnancies and seem to be adequate for interpretation of serum AFP in twins. Therefore, the race-specific singleton multiples are sufficient, obviating the need to build specific median curves for multifetal gestations.

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Section: Commentsmentioning

confidence: 53%

Section: Commentsmentioning

confidence: 67%

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confidence: 99%

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Similarity of Twins to Singleton Maternal Serum Alpha-Fetoprotein Ratio by Race: No Need to Establish Specific Multifetal Tables

et al. 1993

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“…However, the average serum alpha-fetoprotein in twins is 2.04 times higher than singleton pregnancies, the mean unconjugated estriol is 1.64 times greater, and the average human chorionic gonadotropin is 1.93 times higher (51,52). Currently, the reliability of the serum screening for Down syndrome in twins is unknown.…”

Section: Genetic Testingmentioning

confidence: 91%

Management of Multiple Pregnancy: Prenatal Care???Part I

Ayres

Johnson²

2005

Obstetrical & Gynecological Survey

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“…Elevated maternal levels of estrogens [26, 49, 66], progesterone [34], HCG [25, 26, 33], and alpha-fetal protein (AFP) [25, 26, 67], have been found in multiple compared to singleton pregnancies. Investigators have hypothesized that elevated estrogens during a multiple pregnancy may help explain the increased short-term breast cancer risk found in some studies [16, 30, 48].…”

Section: Multiple Births (Table 1)mentioning

confidence: 99%

Pregnancy characteristics and maternal breast cancer risk: a review of the epidemiologic literature

Nechuta

Paneth

Velie

2010

Cancer Causes Control

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The short- and long-term effects of pregnancy on breast cancer risk are well documented. Insight into potential biological mechanisms for these associations may be gained by studying breast cancer risk and pregnancy characteristics (e.g., preeclampsia, twining), which may reflect hormone levels during pregnancy. To date, no review has synthesized the published literature for pregnancy characteristics and maternal breast cancer using systematic search methods. We conducted a systematic search to identify all published studies. Using PUBMED (to 31 July 2009), 42 relevant articles were identified. Several studies suggest that multiple births may be associated with a lowered breast cancer risk of about 10–30%, but results were inconsistent across 18 studies. The majority of 13 studies suggest about a 20–30% reduction in risk with preeclampsia and/or gestational hypertension. Six of seven studies reported no association for infant sex and breast cancer risk. Data are sparse and conflicting for other pregnancy characteristics such as gestational age, fetal growth, pregnancy weight gain, gestational diabetes, and placental abnormalities. The most consistent findings in a generally sparse literature are that multiple births and preeclampsia may modestly reduce breast cancer risk. Additional research is needed to elucidate associations between pregnancy characteristics, related hormonal profiles, and breast cancer risk.

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Maternal serum a-fetoprotein in twin pregnancy

Cited by 27 publications

References 8 publications

Similarity of Twins to Singleton Maternal Serum Alpha-Fetoprotein Ratio by Race: No Need to Establish Specific Multifetal Tables

Similarity of Twins to Singleton Maternal Serum Alpha-Fetoprotein Ratio by Race: No Need to Establish Specific Multifetal Tables

Management of Multiple Pregnancy: Prenatal Care???Part I

Pregnancy characteristics and maternal breast cancer risk: a review of the epidemiologic literature

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