A comparison in maternal and neonatal outcomes between mild fundal pressure and vacuum extraction for shortening the second stage of labor

Abstract

Objective

Mild fundal pressure (MFP) and vacuum extraction (VE) are interventions used during the second stage of labor when clinical intervention is required. While VE is well established with standardized training and predictable risks, MFP remains controversial with limited comparative data. This study aimed to compare maternal and neonatal outcomes of MFP versus VE in women requiring intervention during the second stage of labor.

Methods

This is a retrospective cohort study of women with singleton term pregnancies requiring intervention during the second stage of labor at a tertiary medical center (January 2022–June 2025). Both interventions were appropriate for the same indications; the choice was at physician discretion. The primary outcome was a composite maternal outcome comprising obstetric anal sphincter injury or postpartum hemorrhage. The secondary outcome was a composite neonatal outcome including Apgar score <7 at 5 min, umbilical cord pH <7.1, birth trauma, or neonatal intensive care unit admission.

Results

Of 2389 women, 641 (26.8%) underwent VE and 1748 (73.2%) received MFP. The composite maternal outcome occurred in 13.7% of VE versus 8.7% of MFP (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.45–0.79). The composite neonatal outcome occurred in 10.5% of VE versus 5.2% of MFP (OR 0.47, 95% CI 0.34–0.65), driven by higher birth trauma following VE (4.2% vs. 0.7%). After adjustment, MFP was associated with lower odds of composite maternal outcome (adjusted OR [aOR] 0.56, 95% CI 0.35–0.91) and composite neonatal outcome (aOR 0.57, 95% CI 0.32–0.99).

Conclusion

Mild fundal pressure was associated with lower odds of composite maternal and neonatal adverse outcomes compared with VE.

1. INTRODUCTION

Vaginal birth is generally a physiological process, yet certain circumstances during the second stage of labor may require clinical intervention to ensure maternal and/or fetal well‐being. When non‐reassuring fetal heart rate patterns, maternal exhaustion, or prolonged second stage occur, clinicians may consider techniques intended to achieve timely vaginal delivery. Two interventions commonly used in these situations are mild fundal pressure (MFP) and operative vaginal delivery, specifically, vacuum extraction (VE).

The application of mild fundal pressure remains highly debated in modern obstetrics. A systematic review examining global use demonstrated a pooled prevalence exceeding 23%, yet the maneuver is frequently under‐documented in medical records. ¹ Concerns about maternal safety arise from observational studies reporting associations with severe perineal lacerations, postpartum hemorrhage (PPH), and pelvic floor dysfunction, including levator ani muscle avulsion. ² , ³ , ⁴ , ⁵ , ⁶ However, other clinical studies conducted where fundal pressure is applied gently, selectively, and by trained staff have not demonstrated increased maternal morbidity, suggesting that outcomes might significantly depend on fundal technique and indication. ⁷ , ⁸ , ⁹ , ¹⁰ , ¹¹ The Cochrane systematic review concluded that existing randomized trials were insufficient to determine whether fundal pressure is beneficial or harmful, noting substantial heterogeneity in technique and inadequate reporting of clinical indications. ¹²

In contrast, VE is a well‐established operative method with standardized training, predictable risks, and robust evidence supporting its use. While VE carries known risks, including perineal trauma and neonatal scalp injury, it is supported by clearer guidelines and more consistent outcome data. ¹³ , ¹⁴ Even though MFP and VE are often considered in similar clinical situations, very few studies directly compare these techniques. Most research examines fundal pressure in isolation rather than evaluating it against operative alternatives, leaving clinicians without comparative data to guide decision‐making. ¹⁵

Thus, we aimed to compare maternal and neonatal outcomes associated with MFP versus VE among women requiring intervention during the second stage of labor.

2. MATERIALS AND METHODS

We conducted a retrospective cohort study at a single, tertiary, university‐affiliated medical center with approximately 12 500 deliveries annually. The study was approved by the institutional review board (approval number TLV‐0284‐08), and informed consent was waived due to the retrospective design.

2.1. Study participants

The study included women with singleton term pregnancies and cephalic presentation who required intervention during the second stage of labor from January 2022–June 2025. Indications for intervention included non‐reassuring fetal heart rate or prolonged second stage, defined according to American College of Obstetricians and Gynecologists (ACOG) criteria. ¹⁶ Eligibility required fetal head station at +2 or below. Our institution uses a classification system ranging from −3 to +3, where 0 denotes the level of the ischial spines, with each station representing one‐third of the distance to the pelvic inlet (negative values) or perineum (positive values). In this system, +2 corresponds to approximately +3 to +4 in the ACOG classification (−5 to +5, where each station represents 1 cm). MFP is not performed at higher stations in our institution. Exclusion criteria included trial of labor after cesarean, deliveries using both mild fundal pressure and vacuum extraction, and cases with missing outcome data.

2.2. Study variables

Women were categorized by intervention received: MFP or VE. At our institution, both MFP and VE are considered appropriate interventions for the same clinical indications. There is no institutional protocol mandating one intervention over the other; the choice between MFP and VE is at the discretion of the attending obstetrician based on clinical judgment and provider preference.

At our institution, MFP is performed exclusively by attending obstetricians or senior residents under direct supervision, using gentle, intermittent pressure coordinated with contractions and documented in the medical record, only after patient consent. VE is performed using a standard technique with either a soft cup device or a metal Malmström vacuum extractor (50‐ or 60‐mm diameter).

2.3. Study outcomes

The primary outcome was a composite maternal outcome defined as obstetric anal sphincter injury (OASI) or severe PPH, defined as hemorrhage requiring medical intervention or hemoglobin decrease exceeding 3 g/dL. The key secondary outcome was a composite neonatal outcome defined as Apgar score <7 at 5 min, umbilical artery cord pH below 7.1, clinically significant birth trauma (brachial plexus injury, skull fracture, intracranial hemorrhage, facial nerve palsy, or subgaleal hemorrhage), or neonatal intensive care unit admission.

2.4. Statistical analysis

Continuous variables were compared using t‐tests and categorical variables using χ ²‐tests. Multivariable logistic regression was performed to estimate adjusted odds ratios with VE as the reference category. Covariates were selected based on clinical relevance: nulliparity, second stage duration, epidural anesthesia, body mass index exceeding 30 kg/m², birth weight, and indication for intervention. A sensitivity analysis was performed restricting the cohort to nulliparous women to assess whether findings persisted in a more homogeneous population. Statistical analyses were performed using SPSS version 27, with P < 0.05 considered significant.

3. RESULTS

Overall, 43 295 deliveries occurred at our institution during the study period, of which 2389 women met the inclusion criteria and were included in the analysis. Of these, 641 (26.8%) underwent VE and 1748 (73.2%) received MFP.

Women in the VE group were slightly older (31.8 ± 4.3 vs. 31.2 ± 4.5 years, P = 0.001) and more likely to be nulliparous (94.2% vs. 84.3%, P < 0.001) compared with those in the MFP group. The rate of epidural anesthesia was higher in the VE group (95.3% vs. 91.5%, P = 0.001), as was the mean duration of the second stage of labor (2.18 ± 1.1 vs. 1.82 ± 1.0 h, P < 0.001). A non‐reassuring fetal heart rate was more common in the MFP group (85.0% vs. 71.9%, P < 0.001), whereas a prolonged second stage was more frequent in the VE group (26.7% vs. 15.8%, P < 0.001). Baseline characteristics are presented in Table 1.

TABLE 1.

Baseline characteristics of women undergoing vacuum extraction or mild fundal pressure.

Variable	VE (n = 641)	MFP (n = 1748)	P‐value
Maternal age (years)	31.8 ± 4.3	31.2 ± 4.5	0.001
Gestational age (weeks)	39.6 ± 1.1	39.5 ± 1.2	0.231
Nulliparity	604 (94.2)	1473 (84.3)	<0.001
Pre‐pregnancy BMI (kg/m2)	23.4 ± 4.2	23.6 ± 4.5	0.412
BMI >30 kg/m2	58 (9.0)	172 (9.8)	0.567
Gestational diabetes	72 (11.2)	184 (10.5)	0.624
Hypertensive disorders	38 (5.9)	89 (5.1)	0.432
Induction of labor	245 (38.2)	638 (36.5)	0.446
Epidural anesthesia	611 (95.3)	1599 (91.5)	0.001
Second stage duration (h)	2.18 ± 1.1	1.82 ± 1.0	<0.001
Indication for intervention
Non‐reassuring FHR	461 (71.9)	1486 (85.0)	<0.001
Prolonged second stage	171 (26.7)	276 (15.8)	<0.001
Fetal head station at intervention	2.12 ± 0.4	2.14 ± 0.4	0.342

Note: Data presented as mean ± standard deviation or n (%).

Abbreviations: BMI, body mass index; FHR, fetal heart rate; MFP, mild fundal pressure; VE, vacuum extraction.

The composite maternal outcome occurred in 13.7% of the VE group compared with 8.7% of the MFP group (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.45–0.79, P < 0.001). OASI was higher in the VE group (1.2% vs. 0.4%, P = 0.035). Maternal bleeding was more common in the VE group (12.8% vs. 8.4%, P = 0.002), including PPH requiring intervention (8.0% vs. 5.3%, P = 0.020) and hemoglobin decrease exceeding 3 g/dL (8.1% vs. 4.7%, P = 0.003). Episiotomy was more frequent in the MFP group (35.8% vs. 30.3%, P = 0.013). Maternal outcomes are presented in Table 2.

TABLE 2.

Maternal outcomes in women undergoing vacuum extraction versus mild fundal pressure.

Outcome	VE (n = 641)	MFP (n = 1748)	OR (95% CI)	P‐value
Composite maternal outcomea	88 (13.7)	152 (8.7)	0.60 (0.45–0.79)	<0.001
OASI	8 (1.2)	7 (0.4)	0.32 (0.12–0.88)	0.035
Severe PPHb	82 (12.8)	147 (8.4)	0.63 (0.47–0.84)	0.002
PPH requiring intervention	51 (8.0)	93 (5.3)	0.65 (0.45–0.93)	0.020
Hemoglobin decrease >3 g/dL	52 (8.1)	82 (4.7)	0.56 (0.39–0.80)	0.003
Episiotomy	194 (30.3)	626 (35.8)	1.29 (1.05–1.57)	0.013
Shoulder dystocia	12 (1.9)	28 (1.6)	0.85 (0.43–1.70)	0.649

Note: Data presented as n (%). ^aComposite maternal outcome: OASI or severe PPH. ^bSevere PPH defined as hemorrhage requiring medical intervention (uterotonics, transfusion, or surgical intervention) or hemoglobin decrease >3 g/dL.

Abbreviations: CI, confidence interval; MFP, mild fundal pressure; OASI, obstetric anal sphincter injury; OR, odds ratio; PPH, postpartum hemorrhage; VE, vacuum extraction.

The composite neonatal outcome occurred in 10.5% of the VE group compared with 5.2% of the MFP group (OR 0.47, 95% CI 0.34–0.65, P < 0.001). Birth trauma was significantly more common following VE (4.2% vs. 0.7%, P < 0.001). Umbilical cord pH below 7.1 was observed more frequently in the VE group (2.2% vs. 1.0%, P = 0.042). There was no significant difference in Apgar score below 7 at 5 min or neonatal intensive care unit (NICU) admission between groups. Neonatal outcomes are presented in Table 3.

TABLE 3.

Neonatal outcomes in women undergoing vacuum extraction versus mild fundal pressure.

Outcome	VE (n = 641)	MFP (n = 1748)	OR (95% CI)	P‐value
Composite neonatal outcome a	67 (10.5)	91 (5.2)	0.47 (0.34–0.65)	<0.001
Birth weight (g)	3232.6 ± 390.3	3276.1 ± 394.4	—	0.017
Meconium‐stained fluid	153 (23.9)	346 (19.8)	0.79 (0.63–0.98)	0.031
Birth trauma	27 (4.2)	12 (0.7)	0.16 (0.08–0.32)	<0.001
Apgar <7 at 5 min	3 (0.5)	0 (0)	—	0.018
Umbilical arterial cord pH <7.1	14 (2.2)	17 (1.0)	0.44 (0.22–0.90)	0.042
NICU admission	27 (4.2)	63 (3.6)	0.85 (0.54–1.35)	0.470

Note: Data presented as mean ± standard deviation or n (%).

Abbreviations: CI, confidence interval; MFP, mild fundal pressure; NICU, neonatal intensive care unit; OR, odds ratio; VE, vacuum extraction.

^a Composite neonatal outcome: Apgar score <7 at 5 min, umbilical cord pH <7.1, birth trauma, or NICU admission.

After adjustment for nulliparity, second stage duration, epidural anesthesia, body mass index above 30 kg/m², birth weight, and indication for intervention, MFP remained associated with lower odds of composite maternal outcome (adjusted OR [aOR] 0.56, 95% CI 0.35–0.91, P = 0.019) and composite neonatal outcome (aOR 0.57, 95% CI 0.32–0.99, P = 0.047). The multivariable results are presented in Table 4.

TABLE 4.

Multivariable logistic regression analysis for composite maternal and neonatal outcomes.

Variable	aOR (95% CI)		aOR (95% CI)
	Maternal composite	p‐value	Neonatal composite	p‐value
MFP (vs. VE)	0.56 (0.35–0.91)	0.019	0.57 (0.32–0.99)	0.047
Nulliparity	1.42 (0.78–2.58)	0.251	2.01 (1.05–3.87)	0.036
Second stage duration	1.08 (0.94–1.24)	0.287	1.02 (0.86–1.21)	0.812
Epidural anesthesia	0.89 (0.52–1.53)	0.678	0.76 (0.42–1.38)	0.367
BMI >30 kg/m2	1.18 (0.74–1.88)	0.492	0.92 (0.52–1.63)	0.778
Birth weight (per 100 g)	1.02 (0.98–1.06)	0.412	0.99 (0.94–1.04)	0.654
Non‐reassuring FHR indication	0.87 (0.58–1.31)	0.512	1.24 (0.76–2.02)	0.389

Note: Reference category: vacuum extraction.

Abbreviations: aOR, adjusted odds ratio; BMI, body mass index; CI, confidence interval; FHR, fetal heart rate; MFP, mild fundal pressure; VE, vacuum extraction.

In a sensitivity analysis restricted to nulliparous women (n = 2077), MFP remained associated with lower odds of composite maternal outcome (aOR 0.60, 95% CI 0.37–0.99, P = 0.046). The association between MFP and the composite neonatal outcome was similar but did not reach statistical significance (aOR 0.60, 95% CI 0.34–1.08, P = 0.090).

4. DISCUSSION

In this study, we aimed to compare maternal and neonatal outcomes associated with MFP versus VE among women requiring intervention during the second stage of labor. Our main findings were: (i) MFP was associated with significantly lower odds of composite maternal adverse outcomes compared with VE; (ii) MFP was associated with lower odds of composite neonatal adverse outcomes; and (iii) these associations persisted after adjustment for potential confounders and in sensitivity analysis restricted to nulliparous women.

The lower odds of maternal adverse outcomes with MFP was driven primarily by lower rates of severe hemorrhage, while the lower odds of neonatal adverse outcomes was driven largely by reduced birth trauma. Kanninen and colleagues reported that MFP was associated with modest reduction in second stage duration but also with slightly lower umbilical artery pH and higher rates of low Apgar scores. ¹⁷ Similarly, Akpınar and colleagues found lower neonatal oxygen saturation immediately after birth in the fundal pressure group, although differences resolved within minutes. ¹⁸ However, Eliner and colleagues found that MFP performed by trained obstetricians was not associated with adverse outcomes, ¹¹ and the recent randomized trial by Guo and colleagues demonstrated that MFP reduced operative delivery rates without increasing morbidity. ¹⁹ Our findings align with these latter studies and extend them by directly comparing MFP with VE rather than examining fundal pressure in isolation.

The higher rate of birth trauma in the VE group likely reflects the direct mechanical force applied to the fetal head during this procedure. ²⁰ , ²¹ In contrast, Apgar scores below 7 at 5 min and NICU admission did not differ significantly between groups, suggesting that the neonatal benefit of MFP relates primarily to reduced mechanical injury rather than improved fetal oxygenation. The higher proportion of cases with a non‐reassuring fetal heart rate in the MFP group might explain this pattern, as the fetus might already be compromised at the time of intervention regardless of the technique used. The association with the composite neonatal outcome was less robust than that observed for maternal outcomes and was driven primarily by differences in mechanical birth trauma rather than markers of neonatal acidemia or clinical compromise.

The baseline differences between groups merit consideration. Women in the VE group were more likely to be nulliparous, had longer second stage duration, and more frequently had prolonged second stage as the indication. Residual confounding by indication is likely, as the clinical decision to perform VE versus MFP is influenced by factors not fully captured in our dataset, including fetal head position, degree of descent, urgency of delivery, and provider judgment. The observational design precludes causal inference. The higher episiotomy rate in the MFP group might reflect institutional practice patterns, as episiotomy is sometimes performed to expedite delivery when fundal pressure is applied for fetal indications. Episiotomy was not included in the multivariable model, as it represents an intrapartum intervention that might be influenced by the exposure itself rather than a true baseline confounder. Including episiotomy in the model could, therefore, introduce overadjustment bias.

4.1. Strengths and limitations

The current study has several strengths. The sample size is substantial, providing adequate power to detect clinically meaningful differences. The study was conducted at a single institution with standardized protocols for both interventions, reducing variability in technique. To our knowledge, this is one of the first studies to directly compare maternal and neonatal outcomes between MFP and VE. Restricting inclusion to fetal head station at +2 or lower ensured both interventions were clinically appropriate in the included population, reducing confounding by indication related to head descent. A sensitivity analysis restricted to nulliparous women demonstrated consistent findings, with the maternal association remaining statistically significant.

However, limitations must be acknowledged. The retrospective design might introduce selection bias. Although we adjusted for measured confounders, unmeasured confounding cannot be excluded, and the observational design precludes causal inference. Propensity score methods were not used due to limited overlap in indication profiles between groups. Although MFP is documented in our records, underreporting cannot be excluded. The findings might not generalize to settings where fundal pressure is applied more forcefully or without consistent training. At our institution, MFP is performed exclusively by trained obstetricians; these results should not be extrapolated to settings lacking standardized protocols or formal training. Some individual outcomes, particularly OASI and Apgar score below 7 at 5 min, had low event counts, limiting precision for these specific outcomes. The marked imbalance in group sizes likely reflects local practice patterns and clinician preference, which might limit the generalizability of our findings to settings with different clinical approaches.

4.2. Clinical implications

Several international guidelines advise against routine fundal pressure during the second stage of labor, citing insufficient evidence of benefit and concerns about potential harm. ²² , ²³ Our findings do not contradict this guidance but rather suggest that when MFP is applied selectively, by trained providers, with clear indications and documentation, outcomes might be comparable or favorable relative to VE. Given the observational design and the substantial differences in baseline characteristics and indications between groups, these findings should not be interpreted as evidence of superiority of MFP over VE. Prospective randomized trials comparing these interventions directly are needed before clinical practice recommendations can be modified.

5. CONCLUSION

Mild fundal pressure applied by trained obstetricians was associated with lower odds of composite maternal adverse outcomes compared with VE. The association with neonatal outcomes was less robust and was driven primarily by differences in mechanical birth trauma. These findings suggest that MFP warrants further investigation as an alternative to operative vaginal delivery in selected clinical scenarios. Prospective randomized trials are needed to confirm these findings and establish the appropriate role of MFP in contemporary obstetric practice.

AUTHOR CONTRIBUTIONS

OD: Conception and design of the study, data collection, prepared the main draft of the manuscript. NMG: Data collection and reviewing. RBS: Data collection and reviewing. MRF: Responsible for data analysis. YB: Contributed to the critical review and editing of the manuscript. YY: Supervision, contributed to the critical review and editing of the manuscript. AL: Conception and design of the study, supervision, contributed to the critical review and editing of the manuscript.

CONFLICT OF INTEREST STATEMENT

The authors declare that they have no conflict of interest.

ETHICS STATEMENT

The study was approved by the institutional review board of Tel Aviv Sourasky Medical Center (approval number TLV‐0284‐08). Due to the retrospective nature of the study, the committee waived the requirement for informed consent.

FUNDING STATEMENT

No funds, grants, or other support were received for the conduct of this study.

DATA AVAILABILITY STATEMENT

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.