Perinatal Outcomes in Women with Chronic Kidney Diseases

A retrospective cohort of pregnant women with CKD was followed at the Women's Hospital of Universidade Estadual de Campinas, Brazil, between 2012 and 2020. Variables related to disease etiology, treatment duration, sociodemographic variables, lifestyle, other associated diseases, obstetric history, and perinatal outcomes were assessed. The causes of CKD were grouped into 10 subgroups. Subsequently, we divided the sample according to gestational age at childbirth, as preterm and term births, comparing maternal and neonatal outcomes, and baseline characteristics as well as outcomes among such groups.

Results

A total of 84 pregnancies were included, in 67 women with CKD. Among them, six pregnancies evolved to fetal death, five to miscarriage, and one was a twin pregnancy. We further analyzed 72 single pregnancies with live births; the mean gestational age at birth was 35 weeks and 3 days, with a mean birth weight of 2,444 g. Around half of the sample (51.39%) presented previous hypertension, and 27.7% developed preeclampsia. Among the preterm births, we observed a higher frequency of hypertensive syndromes, longer maternal intensive care unit (ICU) stay in the postpartum period, higher incidence of admission to the neonatal ICU, higher neonatal death, lower 5-minute Apgar score, and lower birth weight.

Conclusion

This study demonstrates increased adverse outcomes among pregnancies complicated by CKD and expands the knowledge on obstetric care among such women in an attempt to reduce maternal risks and identify factors related to prematurity in this population.

Keywords
kidney disease; high-risk pregnancy; antenatal care; perinatal outcomes

		N = 72	%
Age (years)
	< 20	3	4.17
	20–29	35	48.61
	30–39	31	43.05
	≥40	3	4.17
Age (mean)
	28.58 years
Marital status
	Single	26	36.11
	Stable relationship	46	63.89
Occupation^* * 33
	Paid work	11	15.28
	Unpaid work	28	38.89
Schooling^ 21
	Elementary	13	13.06
	High school	33	45.83
	University	5	6.94
Skin color^* ***** 2.
	White	46	63.89
	Non-White	24	33.33
Smoking		2	4.17
Number of Pregnancies
	1	31	43.05
	2	16	22.22
	≥ 3	25	34.73
Previous miscarriage
	0	59	81.94
	≥1	13	18.06

	N = 72	%
Hypertensive syndrome
Chronic hypertension	17	23.61
Chronic hypertension with superimposed preeclampsia	12	16.67
Preeclampsia	8	11.11
Without hypertension	35	48.61
Mode of birth
Vaginal	23	31.94
C-Section	49	68.06
Maternal morbidities after birth^* * Missing 3
Hemorrhage	6	8.33
Infection	4	5.56
Others^** ****** Others: one hypoglycemia, four with hypertensive spikes, one with hypervolemia and dialysis.	6	8.33
None	53	76.61
Maternal ICU admission^ 1
Yes	9	12.50
No	62	86.11
Apgar score at the first minute
<7	14	19.44
≥ 7	57	79.17
Apgar score at the fifth minute^ 1
< 7	3	4.17
≥ 7	68	94.44
Gestational age at birth
GA < 28	4	5.55
≥ 28 GA < 32	5	6.95
≥ 32 GA < 37	25	34.72
GA ≥ 37	38	52.78
Neonatal ICU admission^ 1
Yes	26	36.11
No	45	62.50
Neonatal death^* ***** 4 (no information due to medical transfer of the newborn to another hospital)
Yes	6	8.83
No	62	86.11

Variables	Preterm birth (n = 34)	Term birth (n = 38)	p-value
Maternal age (mean / SD)	29.03 (6.44)	28.18 (6.31)	0.560 ^* * Kruskal-Wallis test,
Years since diagnosis (mean / SD)	10.00 (7.68)	11.13 (9.77)	0.894^* * Kruskal-Wallis test,
Maternal hospitalization in days (mean / SD)	4.85 (2.93)	3.13 (1.44)	0.001^* * Kruskal-Wallis test,
Group of kidney disease			0.143^ Qui-square test,
SLE	8 (23.5%)	13 (34.2%)
Glomerular disease	4 (11.7%)	8 (21.1%)
Nephrotic syndrome	5 (14.7%)	6 (15.8%)
Transplant	4 (11.7%)	6 (15.8%)
Infectious	7 (20.6%)	1 (2.6%)
Hemodialysis	2 (5.9%)	1 (2.6%)
Hypertensive nephropathy	2 (5.9%)	1 (2.6%)
Diabetes nephropathy	2 (5.9%)	0
Others	0	2 (5.3%)
Skin color			0.892^ Qui-square test,
White	23 (67.3%)	23 (63.9%)
Non-white	11(32.7%)	13 (36.1%)
Hypertensive syndrome			0.009^ Qui-square test,
yes	23 (67.7%)	14 (36.8%)
no	11 (32.3%)	24 (63.2%)
Preeclampsia			0.178^ Qui-square test,
yes	12 (35.3%)	8 (21.0%)
no	22 (64.7%)	30 (78.9%)
Mode of birth			0.663^ Qui-square test,
vaginal	10 (29.4%)	13 (34.2%)
cesarean	24 (70.6%)	25 (65.8%)
Postpartum maternal ICU			0.006^ Qui-square test,
yes	11 (34.4%)	3 (11.9%)
no	21 (65.6%)	35 (92.1%)	0.029^ Qui-square test,
Adverse maternal outcome ^# # 2 missing data.
yes	11 (35.5%)	5 (13.2%)
no	20 (64.5%)	33 (86.8%)

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[1] Address for correspondence Fernanda Garanhani Surita, Full Professor, Department of Obstetrics and Gynecology, Universidade Estadual de Campinas, Rua Alexander Fleming, 101, Campinas, SP 13083-881, Brazil. (e-mail:surita@unicamp.br).