Extraordinary weight gain: initial finding in a patient with peripartum cardiomyopathy

Introduction

Peripartum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy presenting with heart failure (HF) secondary to left ventricular (LV) systolic dysfunction towards the end of pregnancy, or in the months following delivery, where no other cause of HF can be found. It is a diagnosis of exclusion. The LV may not be dilated but the ejection fraction (EF) is nearly always reduced below 45% as proposed by the European Society of Cardiology [7]. The presenting symptoms include dyspnea, orthopnea, tachycardia, and peripheral edema [2, 7]. However, as edema is common in healthy pregnant women, and as PPCM is a rare complication occurring in 1 per 3000–4000 women [1], diagnosis of PPCM is often delayed, resulting in major adverse events, such as death or heart transplantation [4].

As all of the common presenting symptoms, such as dyspnea, orthopnea, and peripheral edema, suggest excessive water retention in patients with PPCM, extraordinary weight gain may be an initial finding in some patients with PPCM. However, it has not been well documented whether excessive weight gain actually precedes the onset of PPCM. This case presentation was conducted with the approval of the institutional review board of Hokkaido University Hospital, Sapporo, Japan.

Case presentation

A 33-year-old Japanese woman at gestational week (GW) 34+2 of pregnancy was referred to our hospital as a result of dyspnea and orthopnea. Her dyspnea began at GW 33+2 and she visited a local hospital at GW 34+0, but declined hospitalization despite the referring physician’s strong recommendation. She visited the local hospital 2 days later due to the worsening of dyspnea, and was then transported to our hospital. She had history of one prior birth of a healthy male infant 4 years before the current pregnancy, as well as treatment for depression and an eating disorder. As she believed that depression and the eating disorder had disappeared, she did not take any medicine for these disorders during the pregnancy. The results of physical examinations were as follows: body temperature of 36.4°C, body height of 1.48 m, body weight of 69.1 kg, blood pressure of 95/67 mm Hg with sinus tachycardia of 120 bpm, proteinuria (1+ on dipstick test, 42 mg/dL of protein, and 117 mg/dL of creatinine in spot urine), and marked generalized edema (pitting edema was detected at antenatal cares given at GW 31+2, 33+2, and 34+0). Cardiomegaly with an enhanced vascular shadow and pleural effusion by chest X-ray [cardiothoracic dimension ratio (CTR) of 63%], left ventricular dysfunction by echocardiography [EF, 27%; fractional shortening (FS), 4.0%], and blood B-type natriuretic peptide (BNP) of 2024 pg/mL suggested PPCM. However, the SpO₂ was 99% under room air. The patient gave birth to an otherwise healthy premature male infant that weighed 2576 g after delivery by cesarean section 3 h after admission, which was then admitted to the intensive care unit. Liver dysfunction and hyponatremia (AST/AST, 126/93 IU/L; Na, 120 mEq/L on admission) improved soon after delivery, but cardiac dysfunction persisted (EF, 22%; FS, 8.0%, on postpartum day 39). Diuretics including furosemide and atrial natriuretic peptide were used aggressively after delivery. The patient left hospital on postpartum day 61. The cardiac function improved markedly showing CTR of 40%, EF of 39%, and FS of 20% on postpartum month 9.

Extraordinary weight gain preceded PPCM in this patient (Figure 1); her body weight of 38.5 kg at GW 12+2 increased to 57.5 kg at GW 31+2, 60.6 kg at GW 33+2, 64.3 kg at GW 34+0, and 69.1 kg on the day of delivery at GW 34+2. Her body weight then decreased to 45.2 kg and 37.4 kg on postpartum day 27 and postpartum month 9, respectively.

Figure 1

Perinatal changes in body weight in this patient with peripartum cardiomyopathy.

The shaded area indicates the range of the 2.5^th–97.5^th percentile value obtained from 272 control women with neither hypertension nor pregnancy-induced antithrombin deficiency [10].

Discussion

This patient exhibited an extreme change in body weight during pregnancy and postpartum: weight gain was approximately 1.0 kg/week (22.1 kg/21 weeks) during 19 weeks between GW 12 and 33, 8.5 kg during the last antenatal week (4.8 kg in the last antenatal two days). Thus, this lean woman (body mass index of 17.6 kg/m² at GW 12) gained more than 30 kg of body weight at and after GW 12, suggesting that extraordinary excessive water retention had occurred, especially in the late stage of pregnancy, leading to cardiac overload. The 97.5^th percentile value for weight gain during the last antenatal 2 weeks is 4.0 kg, and that for weight loss during the postpartum month is 13.1 kg in 272 healthy Japanese women [10]. While this patient exhibited a weight gain of 8.5 kg during the last antenatal week and lost her body weight by 24 kg during 4 weeks postpartum. Thus, the majority of the 24 kg lost during 4 weeks postpartum may have been excessively retained water in the late stage of pregnancy in this patient.

Among 128,838 women with singleton pregnancies who were registered with the Japan Society of Obstetrics and Gynecology Successive Pregnancy Birth Registry System (this system was described previously [8]), 1404 (1.1%), 259 (0.20%), and 72 (0.056%) women exhibited weight gain during pregnancy of more than 20 kg, 25 kg, and 30 kg, respectively (corresponding author of this report, Morikawa et al., in publication by J Perinat Med). Thus, weight gain of more than 30 kg during pregnancy seen in our case seldom occurs in Japanese women. We speculate that such women with extreme antenatal weight gain are at higher risk of developing PPCM based on our case. Our speculation was consistent with results of previous studies that a greater weight gain in pregnancy is associated with the development of preeclampsia [9] and women with preeclampsia are at higher risk of developing PPCM [1–5].

As maternal mortality ranges from 4% to 15% [1, 3, 5, 6] and baseline cardiac function at the time of PPCM diagnosis can predict outcome [2–5], increased awareness of PPCM is required for early diagnosis and aggressive therapy in an attempt to prevent complications [4]. Currently known risk factors for PPCM include hypertensive disorders, multifetal pregnancies, and prolonged use of tocolysis [1–5], and do not include excessive antenatal weight gain, perhaps due to a lack of studies dealing with the relationship between the degree of antenatal weight gain and PPCM. We were not able to access reports that focused on the association between maternal weight gain and the development of PPCM. Thus, to our knowledge, this case report is the first to document an extraordinary weight gain during pregnancy in a patient with PPCM. If evidence had been available that antenatal weight gain above a certain cut-off level is a risk factor for PPCM, an earlier examination by echocardiography would have been possible, therefore, we may have found a modestly depressed but better cardiac function than that seen at GW 34+2 in our case. This case highlighted the need for studies addressing the relationship between the degree of antenatal weight gain and the risk of developing PPCM.