INTRODUCTION

The tendency of modern community to give birth at more advanced age conditionedthat prenatal diagnostics methods becamemore frequently used in women's health care. Amniocentesis, a second trimester invasive test, is performed to detect chromosomal numeral andstructural anomalies.¹ However, despite their highsensitivity for detection rates, these procedureshave their complication rates for the fetus andmother, including the fetal fluid embolism.² The risks for fetus include not only miscarriage, with the excess risk of around 0.5-1 % above thebackground risk,³ but also there is a well-provedrelationship between early amniocentesis andcongenital anomaly (talipes).⁴ Despite these raremorphological consequences of amniocentesis, more frequent functional effects may occur thatcan have long-lasting consequences on a child'shealth and are not always observable at prenataland perinatal stages.⁵ Functionally, the fetallungs are extremely sensitive to the externalmechanical effects. There are studies suggestingthat respiratory disturbances such as neonatalpneumonia, meconium aspiration, atelectasisand tachypnea were more frequently found inthe amniocentesis group.⁶,⁷ However, over thelast 10 years, no studies were performed onthe analysis of genetic amniocentesis and fetalrespiratory health. Therefore, the present studyaimed to investigate the rates of respiratory andsleep disturbances in children whose mothersexperienced prenatal amniocentesis.

MATERIALS AND METHODS

RESULTS

Totally we invited 117 mothers, who had indications of amniocentesis, to participate inthe study. 12 were excluded because of detectedpossible prenatal inflammatory state (n = 9) and impact of prenatal smoking (n = 3). 8 mothers were eliminated from the study, because later onthey refused to participate in the study. Finally97 mothers with indications of amniocentesis wereincluded in the analysis. Final data obtained frominfants whose mothers have undergone midtermamniocentesis (n = 50) or no antenatal invasiveprocedure (controls, n = 47) are reported in Table 1.

Table 1 Maternal and infants characteristics expressed as median or n (%) 

There were no differences in bronchiolitis rate between the groups (p < 0.05). However, we detected that asthma diagnosis and sleepdisturbances were more frequent in theamniocentesis group compared with the controls (p < 0.05) (Table 1).

DISCUSSION

The findings of the present study suggest that there are increased rates of asthma inchildren born to mothers subsequent tomidterm amniocentesis. Our data support theresults of other studies which showed thatmidterm amniocentesis may affect the fetallung development,⁷ including the reducedvital capacity of crying in neonates.⁶ In smallchildren, the crying vital capacity is one of thetests indicating the lung function.¹⁰ A causalrelationship between maternal amniocentesisand the lung function deficit may have severalmechanisms. At first, the lost amount of fetalfluids may matter because during midtermamniocentesis about 10-20 ml of fetal fluidsare removed, which is a rather large amountfrom the total of 130-160 ml as estimated at16 weeks of pregnancy.⁶ There are also datasuggesting the need of lowering the amountof the removed fetal fluids in order to reducefetal complication rates.¹ It was estimated thatby only removing 7 ml of amniotic fluid insteadof 15 ml, a total miscarriage rate, incidenceof respiratory difficulties and fixed flexiondeformities is decreased.¹¹ The second mechanismmay be that the process of amniocentesis itselfmay cause the reduction of fetal movements, including breathing which especially manifests24-48 hours after amniocentesis.¹² The reductionof fetal movements after chorionic villus sampling (CVS) or early amniocentesis is a well-knownfactor for other fetal malformations like tapesequinovarus.⁴ It is noteworthy that in animalmodels some histological changes in the lungsoccurred regardless of the time of amniocentesis, the amount of fluid removed and even if themembranes were simply punctured with no fluidremoval.¹³

The relationship between amniocentesis and the increased level of stress is well documented.¹⁴ During stress, the increased maternal cortisollevel may pass through placenta and cause fetalhypothalamus-hypophysis-adrenal activationaccompanied by long-lasting modifications instress reactivity.¹⁴ The findings obtained in ourstudy showed that suspected sleep disturbancesmore frequently observed in the amniocentesisgroup can also be connected with prenatal stresseffects. There are data suggesting that prenatalstress exposure is connected with predispositionto a vulnerability to hyperarousal reactionscontributing to insomnia even in adult life.¹⁵ Of course we can't exclude other possibly notdetected reasons for observed children sleepdisturbances.

After a prolonged pause in scholarly studies examining the link of invasive testing and fetalrespiratory health, the results of our study remindthe fact that amniocentesis may be associatedwith unwanted long-term effects on the child. These data point the need to look for the waysof reducing the numbers of invasive procedures. NIPT (non-invasive prenatal tests) tests may evendecline the need of invasive testing.¹

Our study has some limitations, for example, we have not performed the regression analysisto exclude other possible contributing factors. Also, the number of studied patients is low forthe definite conclusions to be drawn. Annually1000 invasive prenatal procedures are performedin Lithuania. Our cohort represents 5 % of totalamount. Taking into account all these data, every pregnant woman should be providedwith a clear explanation of the differences ofthe prenatal care methods and before giving theinformed consent, should be familiarized withthe invasive procedure, including long termeffects of the child's health.¹ We also highlightthe need for an informed patient consent beforegenetic amniocentesis and the benefit of receivingadequate information on possible alternatives ofinvasive testing.

CONCLUSION

Our data triggers the hypothesis that associations between midterm amniocentesis, child's asthma and sleep disturbances may exist. These preliminary results reveal the importanceof further studies and the need for the analysis oflong term effects of invasive testing.