Applicability of fetal renal artery Doppler values in determining pregnancy outcome and type of delivery in idiopathic oligohydramnios and polyhydramnios pregnancies

Applicability of fetal renal artery Doppler

values in determining pregnancy outcome and type of delivery in idiopathic oligohydramnios and polyhydramnios pregnancies

Zastosowanie analizy dopplerowskiej tętnicy nerkowej u płodu w ocenie stanu noworodka i sposobu ukończenia porodu w ciążach powikłanych małowodziem i wielowodziem

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1 MH Aegean Maternity, Teaching and Training Hospital, Department of Obstetrics and Gynecology, Izmir, Turkey

2 Çanakkale Onsekiz Mart University, Department of Obstetrics and Gynecology, Çanakkale, Turkey

3 MH Aegean Maternity, Teaching and Training Hospital, Department of Radiology, Izmir, Turkey

Abstract

Aims: To investigate the relationship between fetal renal artery Doppler results and pregnancy outcomes in patients with idiopathic abnormal amniotic fluid indices.

Material and method: A total of 110 patients without signs of fetal distress were included in the study: 31 idiopathic oligohydramnios and 29 idiopathic polyhydramnios pregnancies (study group) and 50 normal pregnancies (controls). Doppler investigation of the umbilical artery (UA), middle cerebral artery (MCA), fetal descendant thoracic aorta (DTA) and fetal renal artery (RA) was performed in all patients. Fetal RA resistive index (RI) and pulsatile index (PI) values were measured. Values pertaining to type of birth, newborn weight and APGAR scores were compared.

Results: Average patient age, gravidity and week of pregnancy were 25±4, 1.6, and 37.4±1, respectively. There were no statistically significant differences between the groups as far as UA S/D, MCA S/D, DTA S/D, DTA RI, DTA PI, and RA S/D measurements were concerned. However, in the oligohydramnios group RA RI and RA PI values were significantly higher than the other two groups. Birth weight in the polyhydramnios group and cesarean section rate due to fetal distress in the oligohydramnios group were significantly higher.

Conclusions: In the oligohydramnios group, without affecting fetal distress parameters, Doppler USG evaluation identified an increase in the RA resistance. Also in that group, cesarean rate due to fetal distress during labor was significantly higher than in the remaining two groups. Due to the predictive potential of values of fetal renal artery Doppler of fetal outcome further large sample-sized studies on the subject ought to be carried out.

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Otrzymano: 18.02.2013

Zaakceptowano do druku: 30.09.2013 Corresponding Author:

Ahmet Uysal

Çanakkale Onsekiz Mart University, Department of Obstetrics and Gynecology, Çanakkale, Turkey

Phone: +905332635540;

E-mail: drahmetuysal@hotmail.com

Introduction

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Materials and method

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7Ke Satients Zere eYalXated EetZeen  and  ZeeNs Jestation :omen ZitK amniotiF ÀXid aEnormalities Zere included in the study and age-matched controls were selected.

7he Sregnancies were suEdiYided into three grouSs on the Easis oI the amount oI the amniotic Àuid. 7he Yertical measurement oI amniotic Àuid amount $), was determined Ey transaEdominal ultrasonograShy $/2.$-66'-1 using the  Tuadrant measurement techniTue on areas without comSonents oI the Ietus or umEilical cord. $), less than  mm was classi¿ed as oligohydramnios more than 2 mm was Solyhydramnios with measurements Irom 2-2 mm acceSted as normal Yalues Ior the control grouS. $ll Satients were Iollowed uS till deliYery Ey Ietal EioShysics Sro¿le.

(thical committee aSSroYed oI the study. 'etailed medical history and inIormed consent were oEtained Irom all study SarticiSants. 6uEMects with a history oI smoNing, alcohol consumStion or medication use, SreYious cesarean section, uterine surgery or fetuses with congenital chromosomal anomalies were e[cluded. $ll Satients in the study were chosen from those certain of the dates of the µlast menstrual Seriod¶

andor those who had undergone a Eiometric ultrasound during the 1st trimester. $ll suEMects were giYen Shysical, Yaginal and Eiochemical e[aminations. ,n all the grouSs diastolic and systolic arterial Elood Sressure Yalues -1 mm +g, temSerature measured in the au[iliary region and routine Eiochemical Sarameters, including  gr oral glucose tolerance test, were normal. 1itra]ine tests andor 3520 tests Serformed during the Yaginal e[am were negatiYe. 7here were no suEMects with rhesus incomSatiEility. 2^nd trimester fetal anomaly scans were normal in all Satients. 7hus, care was taNen to ensure that oligohydramnios Streszczenie

Cel: Ocena związku pomiędzy wynikami badania dopplerowskiego tętnicy nerkowej a wynikiem ciąży u pacjentek z idiopatycznym, nieprawidłowym wskaźnikiem płynu owodniowego.

Materiał i metoda: Do badania włączono 110 pacjentek bez objawów zagrożenia życia płodu: 31 z idiopatycznym małowodziem i 29 z idiopatycznym wielowodziem (grupa badana) oraz 50 pacjentek w prawidłowej ciąży (grupa kontrolna). U każdej pacjentki wykonano u płodu badanie dopplerowskie tętnicy pępowinowej (UA), tętnicy środkowej mózgu (MCA), odcinek piersiowy aorty zstępującej (DTA) i tętnicy nerkowej (RA). Zmierzono indeks oporu (RI) oraz indeks pulsacji (PI) w tętnicy nerkowej płodu. Porównano wyniki dotyczące typu porodu, wagi noworodka i skali APGAR.

Wyniki: Średnia wieku pacjentek, liczba ciąż i wiek ciąży w tygodniach wynosiły 25±4, 1.6, 37.4±1, odpowiednio.

Nie wykazano istotnych statystycznie różnic między badanymi grupami w odniesieniu do badanych parametrów:

UA S/D, MCA S/D, DTA S/D, DTA RI, DTA PI, RA S/D. Jednak w grupie pacjentek z małowodziem wartości RA RI oraz RA PI były istotnie wyższe niż w dwóch pozostałych grupach. W grupie pacjentek z wielowodziem, zarówno masa urodzeniowa jak i liczba cięć cesarskich z powodu zagrożenia życia płodu były znacząco wyższe.

Wnioski: W grupie pacjentek z wielowodziem, bez objawów zagrożenia płodu, badanie dopplerowskie wskazało pacjentki z podwyższonym oporem w tętnicy nerkowej płodu. W tej samej grupie liczba cięć cesarskich z powodu objawów zagrożenia życia płodu podczas porodu była istotnie wyższa niż w pozostałych dwóch grupach. Ze względu na potencjalną wartość predykcyjną oceny dopplerowskiej tętnicy nerkowej płodu w przewidywaniu wyniku ciąży powinno się prowadzić dalsze badania na większej grupie pacjentek.

Słowa kluczowe: FLąĪD / SRUyG / WĊWQLFD QHUNRZD / Doppler / ZLeloZoG]Le / / PDáoZoG]Le / Z\QLN FLąĪ\ / DorWD ]VWĊpXMąFD / DorWD pLerVLoZD /

and Solyhydramnios cases included in the study had an idioSathic etiology. 7o determine fetal well-Eeing all Satients were giYen a non-stress test 167 and 167 were reactiYe and the uterine actiYity was not eYident in all grouSs.

$ll 'oSSler inYestigations were carried out in a semi- recumEent Sosition when the fetus was not moYing and during Seriods of resSiratory aSnea. (ach fetus had Eoth Nidneys eYaluated. 7he fetal Nidneys were oEserYed along the longitudinal a[is with the descendant thoracic aorta andor Eilaterally on the transYerse a[is Eeside the sSinal canal. 'oSSler Sarameters for the fetal renal arteries ¹¹ were measured close to the leYel of the aEdominal aorta outÀow. 7o calculate the sSeed from the fetal descendant aorta the angle of intonation was held Eetween 

and  degrees. )or all inYestigations ma[imum systolic sSeed, end-diastolic sSeed, 3, and 5, Yalues were noted. 7he 'oSSler measurements were carried out Ey e[Serienced radiologists while laEor was directed Ey gynecological and oEstetric e[Serts Elinded to the 'oSSler results. 'uring laEor fetal distress was determined Ey late deceleration data on 167 or a SositiYe result of the o[ytocin challenge test. 7he fetuses from the oligo- Solyhydramnios and control grouSs were classi¿ed Ey tySe of Eirth, graYidity and Sarity of the Satient, Eirth weight and 1st and th minute $3*$5 scores and comSared. $ll newEorns underwent a Sediatric e[amination SostSartum and SroYed to Ee normal and healthy.

6tatistical analyses were comSleted using 6366 1.

:indows software. 7he grouSs were comSared using one way

$129$ and chi sTuare tests. 3. was acceSted as statistically signi¿cant.

Results

$Yerage Satient age o was 2.“. 1-, and graYidity was1.“. 1-. 'eSending on the dates of the last menstrual Seriod, the Sregnancies Yaried Eetween  and . weeNs, with an aYerage of .“1. 7here was no statistically signi¿cant difference Eetween the grouS distriEutions in terms of demograShics and Eiometric measurements of the fetus 7aEle ,.

$ll Satients had 'oSSler inYestigations of the umEilical and middle cereEral artery. 7he umEilical artery and middle cereEral artery were determined as systolediastole 6' Yalues on 'oSSler readings. 7here were no statistically signi¿cant differences among the grouSs. $ll Satients had 'oSSler inYestigations of the fetal descendant thoracic aorta '7$ and fetal renal artery 5$.

$gain, there were no statistically signi¿cant differences among the grouSs in terms of fetal '7$ 6' and 5$ 6' Yalues. )etal 5$

5, and 3, Yalues were found to Ee higher in the oligohydramnios grouS and that difference was statistically signi¿cant S.

7aEle ,,.

$s far as Eirth results were concerned, the oligohydramnios grouS had a higher rate of cesarean section  than the Solyhydramnios grouS and controls 1 and 2, resSectiYely. ,n the oligohydramnios grouS Satients with high renal artery 3, Yalues had signi¿cantly higher cesarean rates 11, 1.2 than Satients with low renal artery 3, Yalues 1, . 3 .. ,n the oligohydramnios grouS, 2 cesarean sections were Serformed due to fetal distress 1, non-SrogressiYe laEor  and indication of head-SelYis disSroSortion 1. ,n the Solyhydramnios grouS,  cesarean deliYeries were Serformed due to fetal distress 2, head-SelYis disSroSortion 2 and umEilical cord SrolaSse

1. ,n the control grouS 1 cesareans were Serformed due to fetal distress , head-SelYis disSroSortion , lacN of resSonse to induction 1 and umEilical cord Sresentation 1. 7here was a statistically signi¿cant difference Eetween the oligohydramnios grouS and the remaining grouSs in terms of cesarean Eirth rate S. 7aEle ,,,.

$s for Eirth weights and $3*$5 score, while the oligohydramnios grouS had lower Eirth weights than the control grouS, the Solyhydramnios grouS had higher Eirth weights than the control grouS. 7hese Yalues were statistically signi¿cant S.. 1o differences were found in 1st and th minute

$3*$5 scores Eetween the grouSs 7aEle ,9. Discussion

,n our study the oligohydramnios grouS had signi¿cantly higher renal artery 3, leYels and higher cesarean rates. 3atients in that grouS with high renal artery 3, had the highest cesarean deliYery rates.

,n the literature almost all studies on fetal renal artery 'oSSler in oligohydramnios cases focused on Sost-term Sregnancies and others focused on ,8*5 Sregnancies >, , 1, 12-1@. 7o the Eest of our knowledge, our study is one of the rare few that do not focus on Sost-term or ,8*5 Sregnancies.

$lthough the literature offers studies showing a negatiYe correlation Eetween renal artery 'oSSler and oligohydramnios, some author reSort no link. 2] et al., eYaluated 1 Satients in a study on Sost-term Sregnancies and found that renal artery 'oSSler was the only 'oSSler Sarameter useful for Sredicting oligohydramnios >12@. ,n a different study, where normal amniotic inde[ Sregnancies, oligohydramniotic, Solyhydramniotic and twins where one fetus was oligohydramniotic and the other Solyhydramniotic, Sregnancies were comSared, while there was no relationshiS Eetween Solyhydramnios and renal artery 3,, the renal artery 3, was higher in the oligohydramnios cases >@. 3atient SoSulation in our study was similar to that in the aEoYe mentioned SaSer and, likewise, we found that while Solyhydramnios grouS had no relation to the renal artery 3, inde[, there was an increase in the 3, Yalues, as well as 5, Yalues, in the oligohydramnios grouS.

,n a 11 study, ,8*5 fetuses showed an increased renal artery 3, and a negatiYe correlation of this increase with $),, howeYer there was no such relationshiS in Sost-term Sregnancies

>@. <oshimura et al., showed a negatiYe correlation Eetween oligohydramnios and renal artery 3, in ,8*5 fetuses, as well as those measuring according to dates >@. ,n 2 6elam et al.

eYaluated 1 Sost-term Sregnancies in their study and found that Satients with oligohydramnios had increased rates of renal artery resistance, which were signi¿cantly higher than the umEilical artery and 0&$ resistance rates >1@. 7he authors concluded that in Sost-term Sregnancies arterial redistriEution Slayed a role in the etiology of oligohydramnios. In our study the whole SoSulation was in the rd trimester and there were no Sost-term Sregnancies included. $ll oligo-Solyhydramnios Sregnancies in the study were idioSathic. In all Sregnancies indicators of fetal distress 8$, 0&$, and 167 were all within the normal ranges.

5egardless, the oligohydramnios grouS had increased renal artery 5I and 3I Yalues when comSared to the other grouSs. +oweYer, the source of the fetal renal artery, i.e. the fetal descendant aorta, had normal 'oSSler Yalues.

Table I. Demographic properties of the groups.

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Table II. Doppler values of the groups and their comparisons [11].

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0CA6D “ “ “ 0.08

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5A5,    0.01

5AP, “ “ “ 0.00

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Table III. Type of delivery and numbers by group.

16D C6 Total

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Poli 24  29

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Total 75 35 110

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Table IV. Postpartum babies compared by group.

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It is thought that normal fetal renal 3I and 5I Yalues in Solyhydramnios Satients may indicate that factors affecting the amount of the amniotic Àuid may not Ee limited to renal Yascular eYents. %lood distriEution in the fetus changes in fetal hySo[ia.

'ue to the Erain-sSaring effect, although Elood Àow to the Erain, heart, liYer and adrenal glands does not change, the Elood Àow to SeriSheral organs reduces. :hile Elood Àow in the main carotid artery increases, the renal Elood Àow is reduced Ey 2- >1,

, 1, 1@.

In our study fetal 0&$ 'oSSler readings in all grouSs were normal. In a study on Sost-term Sregnancies no relationshiS Eetween oligohydramnios and renal artery 'oSSler Yalues was shown, howeYer oligohydramnios Sost-term fetuses had signi¿cantly lower Eirth weights than others >1@. In our study, while oligohydramnios EaEies showed no de¿nitiYe difference in Eirth weight than those in the control grouS, they had a signi¿cantly lower Eirth weight when comSared to those in the Solyhydramnios grouS. &ontrary to that study the oligohydramnios grouS in our study had a signi¿cantly higher cesarean rate than the other two grouSs. $lthough the 167 and fetal distress indicators measured uSon entering the study were normal in all grouSs, it seems interesting that the oligohydramnios grouS had a high rate of cesarean sections due to acute fetal distress. 1o seSarate statistical study was done to determine whether that difference was due to Yarying Eirth weights or not, Eecause the cesarean rate was signi¿cantly high in the low Eirth weight grouS already. :hen we look in idioSathic oligohydramnios a study seSarating the fetal renal artery 5I and 3I Yalues into those indicating distress and no distress may Ee called for. &omSaring the two grouSs would determine whether there were differences in tySes of Eirth or not.

7his insight may Ee seen as a limitation to our study. $ small samSle si]e and lack of cord S+ data of the newEorns were the two major limitations of our study.

Conclusions

:hile the Eirth weights of idioSathic oligohydramnios grouS were no different from the control grouS, the Eirth weights in the Solyhydramnios grouS were signi¿cantly higher. $gain in the oligohydramnios grouS, indicators of fetal distress were normal Eut renal artery 5I and 3I Yalues showed increased resistance and, what is esSecially imSortant, this grouS had a signi¿cantly higher rate of cesarean sections due to fetal distress than the other two grouSs.

Authors contributions:

1. Ibrahim Akin – Assumption, study design.

2. Ahmet Uysal – corresponding author – article draft.

3. Fatma Uysal – analysis and interpretation of data.

4. Özgür Öztekin – acquisition of data.

5. Mazaffer Sanci – consept.

6. Aysenur Cakir Güngör revision.

7. Secil Kurtulmus – revision.

8. Cigdem Ispahi – study design.

Authors statement:

1. There is no conflict of interests chich occurs when the author remains In a financial or personal relationship which unjustly affects his/her action associated with the publication of the manuscript.

2. Source of financing – NO.

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