Placenta previa and risk of congenital malformations among singleton births

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DISCUSSION

We found that placenta previa during pregnancy being associated with increased risk of congenital malformations in the offspring with other co-factors such as maternal age,parity,diabetes ,smoking IVF.

    In our study, which was conducted on 90223 patients admitted from three tertiary university-affiliated or teaching Hospitals [Bab El-Shaareia University Hospital_Al Mataria Teaching Hospital_ El Galaa Teaching Hospital]in the period from 2012 to 2015 their age ranged from 16 – 47 years with mean ± SD of (29.63 ± 5.86). 89148 (98.8%) were without placenta previa, 1032 (1.1%) with placenta previa and 43 (0.05%) with placenta previa and accreta.

Parity ranged from (0 -11) with median of 2. Previous cesarean section in admitted women ranged from (0-7) with median 1.

In table (1) we made comparison between women who had placenta previa and women who had not according to maternal age, parity, previous c.s and gestational age. In women without placenta previa age ranged from (16 – 47) with mean±SD (29.59 ± 5.92) and in women with placenta previa age ranged from (17 – 46) with mean±SD (31.75 ± 5.04), parity in women without placenta previa ranged from(0.0 – 11) with median 2.0 (1 - 3) while parity in women with placenta previa ranged from(0.0 – 8) with median 3.0 (2 - 3), in comparison according to Previous CS women without placenta previa who undergone CS ranged from(0.00 – 7) with median 1 and with placenta previa with median2.00 (1 - 3). There was highly statistically significant difference between both groups with p value< 0.001and this study agree with Kancherla et al. ⁶ which was a retrospective population-based study of all singleton births born at or after 22weeks of gestation in Finland during 2000 to 2010 who found that 49% of women had no placenta previa with ages more than 29 years while 57.2 % of them had placenta previa with p value< 0.001 and placenta previa increase in women with previous CS with percentage of 17.2 % in comparison to 10.5 in women without placenta previa with p value < 0.001 and there was no significant difference in parity in both groups.

Our study disagree with Paul et al. ⁹ A case control study conducted on Mulago hospital labour suite Participants: Between 15th November 2001 and 30th November 2002 we identified and recruited thirty six parturients with placenta previa who developed severe bleeding and 180 women with normal delivery. This study found no significant difference between both groups according to maternal age with p value 0.06. also found that parity not found to be risk factors for pp.

In table (1) we found in comparison between women with and without placenta previa that gestational age in case of placenta previa ranged from (23 – 39) weeks with Mean±SD(35.86 ± 2.18) ,while in cases without previa gestational age ranged from (22 – 42)weeks with Mean±SD(36.98 ± 2.91). There was statistically significant difference found between patients with placenta previa and those without placenta previa with p value10, they conducted a retrospective cohort study of singleton births that occurred between 1976 and 2001, examining outcomes including preterm delivery and perinatal complications. Among the 38 540 women, 230 women had previas (0.6%). Compared to controls, pregnancies with previa were significantly associated with preterm delivery prior to 28 weeks (3.5% vs. 1.3%; p = 0.003), 32 weeks (11.7% vs. 2.5%; p < 0.001), and 34 weeks (16.1% vs. 3.0%; p < 0.001) of gestation. Our study also agreed with Kancherla et al. ⁶ who found that there was significant difference between gestational age in both groups with p value

In table (2) in comparison between cases with and without congenital anomalies regarding maternal age we found that cases without congenital anomaly maternal age ranged (16 – 47) with Mean ±SD (29.59 ± 5.87) while in cases with congenital anomaly age ranged 16-45 with Mean±SD31.53 ± 5.29 and there was statistically significant difference in both groups with p value 0.000. Our study agreed with Cleary-Goldman et al. ¹¹ whose study was prospective database from a multicenter investigation of singletons, the FASTER trial, was studied. Subjects were divided into 3 age groups: 1) less than 35 years, 2) 35–39 years, and 3) 40 years and older. Multivariable logistic regression analysis was used to assess the effect of age on outcomes after adjusting for race, parity, body mass index, education, marital status, smoking, medical history, use of assisted conception, and patient's study site. And found that increasing age was significantly associated with congenital anomalies (adjOR 1.4 and 1.7). Also our study in accordance with Parmar et al.¹² whose study was a descriptive, cross-sectional study of newborns and stillborn babies. Total 4210 babies were studied in the neonatal period immediately after birth. Incidence was significantly higher (6.1%) in mothers aged > 30 years as compared to younger age group.

It is well established that advancing maternal age is associated with subfertility, chromosomal abnormalities, and multiple gestation. In patients aged 40 years and older, the higher incidence of antepartum complications such as miscarriage, gestational diabetes, placenta previa, and placental abruption have been documented. The increased incidence of miscarriage is thought to be secondary to the increased risk of chromosomal abnormalities in these pregnancies. The increased risk of gestational diabetes and placenta previa may be secondary to the relationship between aging and progressive vascular endothelial damage resulting in reduced structural and functional health of placenta Cleary-Goldman et al. ¹¹ It has been suggested that increased biological ageing of the ovaries is a major factor for aneuploidy conditions in females -a ‘limited oocytes pool’ hypothesis

 In comparison between cases with congenital anomalies and without regarding smoking we found that smoking increase risk of congenital anomalies, smoking with congenital anomaly cases27(1.3%) while smoking without congenital anomaly represented 0.7%. and there was highly statistically significant difference between both groups with p value 0.000. our study in agreement with Shawky and Sadik ⁸ that found statistically significant difference between cases which represented 55.44% and control 35%with OR 2.310 with p value 8.

In comparison between cases with congenital anomalies and without congenital anomalies regarding diabetes mellitus as a risk factor of congenital anomaly. We found that in cases with congenital anomaly maternal diabetes mellitus represent (9.8%) versus (6.0%) in cases without congenital anomaly and there was statistically significant difference between both groups with p value0.000. our study in agreement with Ordonez et al. ¹³ whose study was review of the records of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) at the University of Chile Clinical Hospital. A sample of 383 mothers with a chronic disease was compared with 297 healthy mothers. The presence of congenital malformations in the newborns was studied. And they found that Offspring of diabetic mothers had 8.95 times more probabilities of having a major malformation and 4.95 times more probabilities of having a minor defect.

 In comparison according to DM our study disagree with Costa et al. ¹⁴ whose study found no significant difference between both groups with p value 0.109, OR 2.07 95%CI (0.83-5.11). Abnormal maternal/fetal fuel metabolism, including hyperglycemia, hyperketonemia, and disordered metabolism of arachidonic acid, myoinositol, and prostaglandin, as well as increased oxidative stress have been shown to be responsible for some of the changes in embryonic high glucose levels during critical periods of morphogenesis appear to be the major teratogen in diabetic pregnancy. An additional possible mechanism is diabetes‐induced hypoxia apparently, due to hyperglycemia ¹⁵.

CONCLUSION

Our study provides further evidence suggesting a weak, but positive association between placenta previa and major congenital malformations, including all structural anomalies, chromosomal defects, and congenital hypothyroidisms, in the offspring. We found increased risk of congenital malformations among infants born to mothers who experienced placenta previa during pregnancy compared with their counterparts, by controlling several important confounders for the first time.