Alka Patil¹, Bhagyashree Badade^2*, Sayli Thavare³

¹Professor and HOD, ²Junior Resident, Department of Obstetrics and Gynaecology, ACPM Medical College, Dhule, Maharashtra, INDIA.

Email: sonu.badade07@gmail.com

Table 4: Neonatal Outcomes associated with Placental Location

The number of central placentas having NICU admissions were 24(14.6%) and without NICU admissions were 142(85.4%). The number of lateral placentae with NICU admissions were 9(29.3%) and without NICU admissions were 23(70.7%).

Table 5: Placental Location and NICU Admissions

Graph 6: Placental locatin and NICU Admissions

DISCUSSION

Uteroplacental circulation and studies examining the association between placental location and uterine artery Doppler velocimetry suggest that site of placental attachment in the uterus may be an important determinant of placental blood flow. Abnormal uterine artery blood flow is more likely to occur in pregnancies with unilaterally located placentas. This suggests the possibility that placental location might affect fetal growth.² Various factors associated with IUGR are maternal malnutrition, infectious agents, maternal vascular disease which have been hypothesized to exert their effects on foetal growth by constraining foetal resources by restricting metabolic substrates, limiting oxygen availability, or curbing foetal blood supply. Given the placenta’s role in fetal blood supply, nutrient and oxygen delivery, it comes as little surprise that placental location itself elevates the risk of IUGR.² The maternal blood supply to the placenta derives mainly from the uterine arteries, with additional supply from the ovarian arteries.⁶ In pregnancies with unilateral placentas, uterine artery resistance is lower in the ipsilateral vs. contralateral uterine artery, while in pregnancies with centrally located placentas resistance is similar between the two uterine arteries.² Ito et al., interpreted this finding in the context of an electrical equivalent circuit model of uteroplacental circulation and suggested that the decreased placental-side uterine artery resistance may reflect decreased uteroplacental blood flow volume in unilaterally situated placentas.⁷ Kofinas (64), further suggested an anatomic mechanism by which decreased blood flow to a unilaterally located placenta could occur. Perhaps centrally located placentas receive adequate blood flow from both uterine arteries by virtue of their position. Therefore, any deficiency in circulation could lead to decreased blood flow, and, therefore, a higher risk of growth restriction in pregnancies with unilateral placentas.⁸ In our study we found that, out of 200 women, the frequency of central placentation was 166(82.8%), that of lateral placentation was 32(16.2%) and 2(1%) of placenta previa, which was comparable with the study done by Vidhu Nair et al.,³ Jaiswal et al.,⁹ Singh et al..¹⁰

Table 6:

In the study conducted by Vidhu Nair et al.,³ out of 450 singleton pregnancies, central placentation with abnormal outcome was 182(48.3%) and normal outcome was 195(51.7%). The number of lateral placentas with abnormal outcome was 44(60.3%) and with normal pregnancy outcome was 29 (39.7%). In their study, Lateral placentas had the major abnormal outcomes which was comparable to our study, where out of total cases, 89(53.7%) cases with central placentation had normal outcome and 77(46.3%) had abnormal outcome, whereas lateral placentas with normal outcome were 14(42.8%) and abnormal outcome was seen in 18(57.2%)cases.

Similarly, Singh et al.¹⁰ also concluded that lateral placenta was associated with more abnormal outcomes, compared to centrally located placentas.

Table 7.

In anteriorly located placentas, the incidence of IUGR is found to be 3.3%, preterm birth 10%, and 5% were IUFD. Similar observations were made by Fung et al.,¹¹ where 13 cases of anterior placenta were associated with 7.3% risk of IUD/still birth. Shakluntala Chhabra et al.,¹² in their study reported that with anterior placenta, 10 (5%) women had spontaneous preterm labor. Shumaila Zia et al.¹³ conducted a retrospective study on 474 patients and found that anterior placental location was associated with IUD with an outcome of 1.5%. The study also showed statistically significant association of anterior placenta with IUGR and IUFD. With Fundal location, the incidence of IUGR is found to be 15%, preterm birth 16%, and that of IUFD is 5.1% which is comparable to study done by Shakluntala Chhabra et al.,¹² where out of 322 women with fundal placenta, 28 (42.4%) had FGR, 34 (10.6%) had preterm births. Hadley et al.¹⁴ reported that a placenta located in the fundus carries a significantly higher risk of premature rupture of the membrane. Shumaila Zia et al.¹³ revealed a significant association of fundal placentas with IUGR. In our study, with posterior placental location, the incidence of IUGR is found to be 7.4%, preterm birth 14%, and that of IUFD is 4%. This result was correlating with the study done by Singh et al.,¹⁰ which concluded that posterior placental location was associated with 62.26% risk of IUGR. Similarly, in the study done by Shakluntala Chhabra et al.,¹² (4 of 12) had FGR, 18 (14.6%) women had spontaneous preterm labor. Similar observations were made by Fung et al.,¹¹ Shumaila Zia et al.,¹³ in their study concluded that preterm labour was associated with posterior placenta with an outcome of 3.7%. Singh et al. ¹⁰ concluded that posterior placental location had 50% risk of still birth. In present study with lateral placental location, we found the incidence of IUGR was 16%, preterm birth was seen in 31%, and 3% were IUFD. These results were in accordance with the study conducted by Vidhu Nair et al.,³ where five cases of left lateral placenta were associated with IUGR and abnormal dopplers (10.2%) and Eight cases of left lateral placenta were associated with 16.3% risk of preterm birth. Similarly, Singh et al.¹⁰ conducted a prospective study on 592 patients and concluded that lateral placental location was associated with 62.26% risk of IUGR. Seadati et al.,¹⁵ showed lateral placentation had 2.7 times risk of developing IUGR. A retrospective study conducted by Jackson et al.¹⁶ showed lateral placenta was associated with preterm birth. Kofinas et al.⁸ used a case-control design to compare placental location in pregnancies with IUGR and/or preeclampsia to placental location in normal pregnancies. They found that in the presence of preeclampsia and/or IUGR, up to 75% of pregnancies had unilaterally located placentas and 25% central placentas, whereas in the absence of these two conditions, 51% of the patients had unilateral and 49% central placentas. Additionally, in the assessment of laterally implanted placenta, Vaillant et al.¹⁷ discovered an increased risk of fetal distress, caesarean deliveries, and IUGR compared with centrally implanted placentas. A more recent study by Magann et al.,¹⁸ however, examined second trimester placental location and a variety of adverse pregnancy outcomes. This group found an association between unilateral implantation and low Apgar scores (<7) at 1 and 5 minutes 30, which was consistent with our study, where it was observed that lateral placenta had Low APGAR score at 1minute and 5minute.

Table 8:

The current study showed, lateral placenta had major NICU admissions. The number of central placentas having NICU admissions were 24(14.6%) and without NICU admissions were 142(85.4%). The number of lateral placentae with NICU admissions were 9(29.3%) and without NICU admissions were 23(70.7%), these results were consistent to the study done by Vidhu Nair et al.,³ where the number of central placentae having NICU admissions were 62 (16.4%) and the number of lateral placentae with NICU admissions were 19 (26%), the number of central placentae without NICU admission were 315 (83.6%) and lateral placenta without NICU admission were 54 (74%). Singh et al.¹⁰ concluded that 16% of NICU admissions belong to the high-risk group of IUGR.

CONCLUSION

In our study, there is a significant association between lateral placentation and abnormal neonatal outcomes. Therefore, our findings suggest that some aspect of placental implantation in the lateral uterus makes it less favourable for fetal growth than implantation in other sites. Therefore, placental location by Ultrasound examination done in second trimester is used as non-invasive predictor in determining adverse neonatal outcomes.

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