^

Health

You are here

A
A
A

A pregnancy-associated protein A in the blood (PAPP-A)

 
, medical expert
Last reviewed: 31.05.2018
 
Fact-checked
х

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

A pregnancy-associated plasma protein A (PAPP-A) was detected in the serum of pregnant women in 1974. The protein has a molecular weight of 820,000, a tetrameric structure, a developed carbohydrate component, and a pronounced affinity for heparin. The molecule PAPP-A has a structure identical to α 2 -macroglobulin, which is an inhibitor of almost all known proteinases.

In pregnancy, as well as in some malignant and inflammatory diseases, there is an increase in the biosynthesis of PAPP-A, which is manifested by an increase in its concentration in the blood serum. During pregnancy, the content of PAPP-A in the blood increases thousands of times and before delivery may exceed 200 μg / ml. The concentration of PAPP-A in the serum in primiparous women and in women with a history of three pregnancies and more is reduced. Quite often, with a high concentration of PAPP-A, the placenta mass is also increased. Multiple pregnancy, as a rule, is accompanied by a high content of PAPP-A in the serum. After delivery, there is a rapid decrease in the level of PAPP-A within the first 2-3 days, and then its concentration decreases by an average of 2 times every 3-4 days.

In case of a threatening miscarriage accompanied by bleeding (8-14 weeks of pregnancy) and development of intrauterine hematomas, the volume of which does not exceed 15 ml, the concentration of PAPP-A in the blood does not change significantly. In women with bleeding at 7-20 weeks of pregnancy, a low concentration of PAPP-A in the blood is detected more often than with a normal pregnancy. In addition, approximately 10% of women whose pregnancy ended with miscarriage, PAPP-A concentrations in the serum were elevated.

Virtually all women with low placenta have a less pronounced increase in PAPP-A concentrations in the blood throughout the pregnancy.

In women with a normal placenta, premature birth and fetal hypotrophy are most often observed when a low level of serum PAPP-A occurs at the 7th to 13th week of pregnancy.

At the end of pregnancy, the concentration of PAPP-A in the serum, as well as its total content in the placenta in women suffering from diabetes, is significantly lower than with a normal pregnancy. Reduction of these indicators before birth was also recorded in pregnant women with arterial hypertension in the anamnesis.

An increase in serum PAPP-A for a gestation period of 34 weeks is found in women with severe late gestosis, which often precedes the clinical manifestations of pre-eclampsia, and is also possible with increased diastolic pressure. Often, a high content of PAPP-A in the blood for a period of 34 weeks is found in those pregnant women who subsequently have premature birth or the postpartum period is complicated by bleeding.

Change in serum PAPP-A concentration in pathological variants of pregnancy

Type of pathology

PAPP-A

Miscarriage

↓ (I-II)

Fetal hypotrophy

↓ (I)

Fetal trisomy

↓ (I)

Diabetes

↓ (III)

Chronic hypertension

↓ (III)

Preeclampsia

↑ (III)

Premature birth

↓ (I); (III)

Postpartum hemorrhage

↑ (III)

Primarily low placentation:

Absence of complications

↑ (I-III)

Fetal abnormalities

↓ (I); ↑ (II, III)

Fetal hypotrophy

↓ (I); ↑ (II-III);

Late miscarriage

↑ (I); ↓ (II);

Prematurity

↑ (III)

Note: ↑ - increase, ↓ - decrease. The trimester of pregnancy is indicated in parentheses.

trusted-source[1], [2], [3], [4], [5], [6], [7], [8], [9]

It is important to know!

At week 22 the baby has already grown to 28 cm and weighs almost 0.5 kg. His lips, eyelids, and eyebrows are more distinct and he even begins to form tiny teeth in the gums. Read more..

!
Found an error? Select it and press Ctrl + Enter.
You are reporting a typo in the following text:
Simply click the "Send typo report" button to complete the report. You can also include a comment.