High Blood Pressure in the Birth Room: Epidemiology and Outcome of Pregnancies at the General Hospital of Loandjili (Pointe-Noire, Congo)

Objective: According to the World Health Organization, blood pressure disorders of pregnancy constitute a real public health problem of worldwide scope. It is an important factor of gravity, provider of a high maternal and perinatal morbidity and mortality in our maternities. The aim of this work is to study the epidemiological profile of pregnant women with hypertension and the outcome of their pregnancy. Methods: Descriptive cross-sectional study, carried out from January 1 to December 31, 2019, in the birthing block of the Obstetrics Gynecology service of the Loandjili General Hospital in Pointe-Noire, having included exhaustively and consecutively, all of them having given birth high blood pressure from a theoretical or ultrasound term of at least 22 weeks of amenorrhea or a birth weight of at least 500 g according to the WHO. New-borns of hypertensive mothers were also considered. The variables studied were socio-demographic, reproductive, linked to monitoring of pregnancy, clinical, relating to childbirth and maternal and perinatal prognosis. Results: Eighty and fourteen hypertensive pregnancies were recorded among 1677 admitted to the birthing room, a frequency of 5.6%. They were of a median age of 33, predominantly employed (60%), multigest (69%) and multiparous (44%). They were the most referred (66%) and admitted for high blood pressure or its complications in more than three quarters of cases (78%). Delivery was premature in more than half of the cases (54%), either spontaneously or induced. In this context, caesarean section was the preferred delivery route (77% of cases), performed urgently (94.4%) for severe maternal morbidity. Indications for emergency caesarean section were dominated by severe preeclampsia (67%), retroplacental hematoma (14%) and eclampsia (11%). One case of maternal death has been noted. Stillbirth was noted in 5% of cases (n=5). Neonatal morbidity was represented by poor adaptation to ectopic life (n=24 or 27%), hypotrophy (n=3 or 14%), prematurity (n=19 or 20%), neonatal resuscitation (n=24 or 27%) and the transfer to neonatology (n=45 or 48%). Conclusion: The association of high blood pressure and pregnancy remains frequent in our maternities. Given its high morbidity and mortality, it poses a real challenge for the obstetrician as to the outcome of pregnancies. The obstetrical prognosis and the improvement of the maternal and new-born prognosis go through the promotion of quality prenatal contacts and prevention.


Introduction
Defined as diastolic blood pressure greater than or equal to 90 mmHg, whether associated with systolic blood pressure greater than or equal to 140 mmHg [1], hypertension during pregnancy remains common. According to the World Health Organization, blood pressure problems in pregnancy are a real public health problem of worldwide scope [1][2][3]. Hypertensive disorders of pregnancy constitute one of the leading causes of maternal and perinatal mortality worldwide. It has been estimated that high blood pressure complicates 2-8% of pregnancies globally including 2.4% in Congo [4][5][6]. In Latin America and the Caribbean, hypertensive disorders are responsible for almost 26% of maternal deaths, whereas in Africa and Asia they contribute to 9% of deaths. Although maternal mortality is much lower in high-income countries than in developing countries, 16% of maternal deaths can be attributed to hypertensive disorders [4,7]. Indeed, hypertensive pregnancy disorders are the second leading cause of maternal death worldwide and the leading cause of perinatal morbidity and mortality [7].
Therefore, it remains an important factor of gravity, provider of high maternal and perinatal morbidity and mortality in our maternities. Thus, the present study set itself the objective of studying the epidemiological profile of pregnant women with hypertension and the outcome of their pregnancy.

Methods
This was a descriptive cross-sectional study, carried out from January 1 to December 31, 2019, in the delivery block of the Obstetrics Gynecology service of the Loandjili General Hospital in Pointe-Noire. We included exhaustively and consecutively, all women having presented hypertension from a theoretical or ultrasound term of at least 22 weeks of amenorrhea or a birth weight of at least 500 g depending on the WHO [1]. New-borns of hypertensive mothers were also considered. Hypertension has been defined by the WHO by measuring a diastolic blood pressure greater than or equal to 90 mmHg associated or not with a systolic blood pressure greater than or equal to 140 mmHg [1].
The variables studied were socio-demographic (age, professional activity, marital status, mode of admission), reproductive (pregnancy, parity), linked to monitoring of pregnancy (prenatal contacts), clinical (term of pregnancy, reasons for admission), relating to childbirth (route, type and indications of caesarean section) and maternal and perinatal prognosis.
The birth weights were projected onto the weight curve as a function of gestational age [8,9] in order to assess the degree of percentile defining fetal growth. Thus, hypotrophy was defined by a birth weight lower than the 10th percentile compared to the gestational age.
Epi-Info 7.1 software was used for statistical analysis. Qualitative variables were represented as a proportion.
Quantitative variables, on the other hand, were represented as the mean and its standard deviation, or as the median and its quartiles (q1, q3).

Results
Pregnant women with hypertension represented 5.6% of admissions to the birth room, i.e. 94/1677. They were of a median age of 33 (26, 36) with extremes of 18 to 45. The other socio-demographic characteristics are shown in Table 1. Their pregnancy was followed in almost the most of cases (95%) with an average number of prenatal contacts of 5±0.3. They were mainly multigest (69%) and multiparous in almost half of the cases (44). They were in two thirds of cases (66%) referred and admitted for hypertension or its complications in more than three quarters of cases (78%). In the remaining quarter, high blood pressure was diagnosed in the delivery room. In this context, childbirth was premature in more than half of the cases (Table 2), either spontaneously or induced. Pregnant women gave birth more by caesarean section (n=72 or 77%). Caesarean section was performed in an emergency in 94.4% (n=68) either before entering labour (n=66), or during labour (n=2). In the remaining cases the caesarean was prophylactic. The indications for caesareans are reported in Table 3. Emergency caesarean sections before entering labour represented maternal morbidity linked to high blood pressure. Among them, in the postpartum period, there was one case of stroke and one death in the context of acute lung oedema.
Stillbirth represented 5% of cases (n=5). The new-borns were resuscitated in 27% of cases and transferred to neonatology in almost half of the cases (48%) for low birth weight and prematurity (n=21) and poor neonatal status (n=24). The neonatal characteristics are shown in Table 4. Figure 1 shows the point cloud of birth weights relative to term. Death in neonatology represented 9% of cases.

Discussion
Although twice as high as that reported in Brazzaville by Itoua [6] and far below the 8.2% observed in the Cameroonian series [10], the frequency of high blood pressure in pregnant women in our series remains in the limits of that found in the literature, varying between 2 and 8% [4][5][6]. Its distribution among pregnant women is uneven, observing a predominance of young adult patients close to their thirties, multiparous and admitted indirectly in an emergency context. As reported by Tshabu-Aguemon in Benin, an average age of mothers of 26.4 +/-6.3 years (16 -40 years), out of school and mainly referred in three quarters of cases [11]. This profile almost found in African series can be explained on the one hand by socio-cultural similarities and on the other by overlapping difficulties relating to the organization of the health system. In addition, the early onset of arterial hypertension before 28 weeks of amenorrhea, contributed as to Brazzaville [6], to a high maternal morbidity dominated by severe preeclampsia with repercussions on fetal growth, hematoma retroplacental and eclampsia. Similar observations have been reported in the Benin series in different proportions. The authors noted the predominance of eclampsia and retroplacental hematoma in 36.8% and 7.4% of cases, respectively; this more significantly (p <0.05) in pregnant women referred [11]. Hypertensive disorders of pregnancy are associated with high maternal morbidity and are responsible for a cardiovascular risk. Thus, according to the data from the study by OLIE in France, chronic hypertension would increase the risk of pulmonary embolism (RR=2. 5 [12]. This would explain the high proportion of emergency caesareans observed in the African series in comparison with the Western series where the caesareans would be more prophylactic due to the availability of predictive diagnostic means (uterine doppler) and monitoring (fetal dopplers, automated heart rate analysis fetal, biological assessment of high blood pressure). Also, the prevention of hypertensive disorders by early salicylotherapy would contribute to the reduction of severe and early forms in pregnant women with a vascular risk [1,13]. Which could explain a higher proportion of vaginal deliveries than ours. Severe maternal hypertensive morbidity has been deleterious for new-borns. These, as in several other African series, were the most hypotrophic and premature with difficulty adapting to ectopic life, leading to a significant transfer to neonatology after resuscitation [14][15][16]. The risk of preterm birth of new-borns from hypertensive mothers is five times higher compared to those of non-hypertensive mothers (OR=4.8 [1.57-13.36]) [16]. In most cases, this is prematurity most often induced by fetal extraction for maternal rescue caesarean section or severe fetal morbidity. Thus, in more than half of the cases, the pregnant women of our series gave birth prematurely, explained by a maternal morbidity dominated by severe preeclampsia, retroplacental hematoma and eclampsia. Likewise, Boiro in France has reported perinatal morbidity predominated by prematurity, low birth weight, growth retardation, respiratory distress and perinatal asphyxia [17]. In the Congolese series, the authors note an excess risk of low birth weight multiplied by 5 in the event of blood pressure disorders (OR=5.5 [2.08 -14.8]) [14].
Maternal and neonatal morbidity and mortality linked to high blood pressure during pregnancy, remains high in sub-Saharan Africa [5,6,10,11,[14][15][16], despite the mobilization of comprehensive emergency obstetric and neonatal care (SONUC). Therefore, as noted in the literature, only quality essential obstetric care can significantly improve this prognosis.

Conclusion
The association of high blood pressure and pregnancy remains frequent in our maternities. Given its high morbidity and mortality, it poses a real challenge for the obstetrician as to the outcome of pregnancies. The obstetrical prognosis and the improvement of the maternal and new-born prognosis go through the promotion of quality prenatal contacts and prevention.

Conflicts of Interest
All the authors do not have any possible conflicts of interest.