Evidence for the participation of CHCHD2/MNRR1, a mitochondrial protein, in spontaneous labor at term and in preterm labor with intra-amniotic infection

Figures & data

Figure 1. Flow diagram of patients included in the study.

Figure 2. Concentration of CHCHD2/MNRR1 (pg/mL) in the amniotic fluid of pregnant women in the mid-trimester, at term without labor and at term with labor. Data are reported as medians and interquartile ranges. The analysis was performed after log₂ transformation of the data.

Table 1. Clinical characteristics of women in the mid-trimester of pregnancy and at term with and without labor.

	Mid-trimester (n = 16)	Term no labor (n = 22)	p*	Term in labor (n = 37)	p**
Maternal age (years)	36.5 (33.5–39.7)	29.5 (19.7–35.0)	<0.001	22.0 (19.5–24.5)	0.07
Nulliparity	31.3% (5)	25% (5/20)^α	.7	50% (18/36)^α	.1
GA at amniocentesis (weeks)	16.1 (16.0–16.9)	38.7 (38.0–40.0)	<0.001	35.8 (37.7–39.2)	.4
GA at delivery (weeks)	39.5 (39.0–40.0)	38.7 (38.0–40.0)	.09	38.5 (37.7–39.2)	.4
Duration of sample storage (years)	26.9 (25.8–27.4)	31.6 (31.6–31.7)	<0.001	31.6 (31.3–31.7)	.6
Birthweight (grams)	3460 (3261–3923)	3230 (3031–3686)	.07	3390 (3040–3545)	.9

GA: gestational age. Data are reported as the median (interquartile range) for continuous variables and as a percentage (number) for dichotomous variables; ^αmissing values.

p* compared between mid-trimester vs term no labor; p** compared between term no labor vs. term labor.

Figure 3. Concentration of CHCHD2/MNRR1 (pg/mL) in the amniotic fluid of pregnant women in preterm labor classified by gestational age at delivery and the presence of intra-amniotic inflammation. Data are reported as medians and interquartile ranges. The analysis was performed after log₂ transformation of the data.

Figure 4. Concentration of CHCHD2/MNRR1 (pg/mL) in the amniotic fluid of pregnant women in preterm labor with intra-amniotic inflammation classified by the presence or absence of microbial invasion of the amniotic cavity. Data are reported as medians and interquartile ranges. The analysis was performed after log₂ transformation of the data.

Table 2. Clinical characteristics of women with preterm labor according to the gestational age at delivery (preterm and term) and to the presence of intra-amniotic inflammation.

	Preterm labor and term delivery, without intra-amniotic inflammation (n = 25)	Preterm labor and delivery, without intra-amniotic inflammation (n = 47)	p*	Preterm labor and delivery, with intra-amniotic inflammation (n = 53)	p**	p***
Maternal age (years)	23.0 (20.5–28.5)	23.5 (20.0–26.5)	.8	23.0 (20.0–28.0)	.9	.8
BMI (kg/m^2)	23.7 (20.8–30.7)	23.2 (19.6–28.9)	.5	25.8 (20.5–32.6)	.2	.7
Tobacco use	16.0% (4)	21.7% (10/46)^a	.8	21.2% (11/52)^a	.9	.8
Nulliparity	20.0% (5)	31.9% (15)	.3	30.2% (16)	.9	.3
GA at amniocentesis (weeks)	31.6 (30.5–32.6)	31.6 (28.6–32.7)	.7	25.6 (23.5–31.8)	<.001	<.001
GA at delivery (weeks)	38.7 (37.8–39.6)	34.8 (33.4–36.0)	<.001	26.6 (24.4–32.3)	<.001	<.001
Duration of sample storage (years)	16.2 (14.6–16.5)	15.4 (13.9–16.6)	.3	16.2 (13.4–17.0)	.8	.6
Birthweight (grams)	3065 (2807–3340)	2330 (1935–2645)	<.001	910 (610–1892)	<.001	<.001

BMI: body mass index; GA: gestational age. Data are reported as the median (interquartile range) for continuous variables and as a percentage (number) for dichotomous variables; ^amissing values.

p* compared between preterm labor and term delivery without intra-amniotic inflammation vs. preterm labor and delivery without intra-amniotic inflammation;

p** compared between preterm labor and delivery without intra-amniotic inflammation vs. preterm labor and delivery with intra-amniotic inflammation;

p*** compared between preterm labor and term delivery without intra-amniotic inflammation vs. preterm labor and delivery with intra-amniotic inflammation.

Table 3. Clinical characteristics of women with preterm birth and intra-amniotic inflammation in the presence or absence of microbial invasion of the amniotic cavity.

	Preterm birth with sterile intra-amniotic inflammation (n = 37)	Preterm birth with microbial-associated intra-amniotic inflammation (n = 16)	p
Maternal age (years)	23.0 (20.0–25.7)	24.0 (20.0–31.0)	.2
BMI (kg/m^2)	23.2 (19.6–32.4)	26.5 (23.5–35.1)	.2
Tobacco use	22.2% (8/36)^α	18.8% (3)	1.0
Nulliparity	27.0% (10)	37.5% (6)	.5
GA at amniocentesis (weeks)	24.7 (23.3–30.5)	26.3 (23.8–32.3)	.3
GA at delivery (weeks)	26.6 (24.2–32.1)	26.7 (24.8–32.6)	.9
Duration of sample storage (years)	15.3 (13.4–17.0)	16.3 (13.7–17.4)	.4
Birthweight (grams)	910 (558–1907)	913 (672–1877)	.8

BMI: body mass index; GA: gestational age; Data are reported as the median (interquartile range) for continuous variables and as a percentage (number) for dichotomous variables; ^αmissing values.

Data availability Statement

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author at [email protected] (Dr. Romero).