Efficacy of Cabergoline in Inhibiting Lactation and Alleviating Breast Symptoms After 12-18 Week Abortion or Pregnancy Loss: A Pilot and Randomized Controlled Trial
Phase: PHASE2
Conditions: Pregnancy, Abortion
Sponsor: Maimonides Medical Center

TITLE Efficacy of Cabergoline in Inhibiting Lactation and Alleviating Breast Symptoms After 
12-18 Week Abortion or Pregnancy Loss: A Pilot and Randomized Controlled Trial 
 
PRINCIPAL INVESTIGATOR June Ng, MD MPH (JuNg@maimo.org) 
 
CO-INVESTIGATORS  Kathleen Morrell, MD MPH (KMorrell@maimo.org), Heather Gold, 
MD MPH (HeGold@maimo.org), Lily Berkin (lily.berkin@downstate.edu), Olivia Sher, MPH 
 
FUNDING SUPPORT  
Maimonides Research and Development Foundation 
 
APPROVAL DATE 
February 27, 2026 
 
APPROVAL NUMBER 
2025-07-24 
 
NCT 
NCT ID not yet assigned 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
INTRODUCTION 
 
BACKGROUND AND SIGNIFICANCE 
 
Second-trimester spontaneous and induced abortions are often accompanied by 
significant physical discomfort. While patients and providers usually focus on pelvic pain, breast 
symptoms are actually very common, as lactogenesis begins as early as 12-20 weeks of 
gestation. For example, Hagey et al found that 50% of patients undergoing abortion or pregnancy 
loss between 14 and 20 weeks experience breast tenderness, while 45% report breast 
engorgement, and 20% report lactation.2 However, the frequency of breast symptoms in the early 
second trimester has not been adequately assessed. 
Due to the bothersome and potentially upsetting nature of these symptoms, several 
studies have aimed to identify a pharmacologic solution to stop pregnant people from 
experiencing them. A randomized controlled trial in 1990 identified that bromocriptine was 
effective at inhibiting lactation and breast symptoms for induced or spontaneous abortions 
between 15 and 26 weeks.3 However, bromocriptine was also found to be associated with 
significant cardiovascular, neurologic, and psychiatric side effects, and, in two patients, death.4 
In fact, bromocriptine was pulled from the US market for lactation suppression due to these 
concerns.5 Cabergoline then emerged as a possible safer lactation suppression medication. The 
drug is a newer ergot derivative, part of the same drug class as bromocriptine, that lowers the 
activity of prolactin, a hormone that is needed for lactation.6 Two subsequent systematic reviews 
identified cabergoline as not only safe to use for lactation suppression, but also associated with 
less dizziness, headache, and nausea compared to bromocriptine.7,8 Subsequently, two trials and 
a review found that cabergoline is as effective as bromocriptine in suppressing lactation 
symptoms.6,9 However, these studies assessed lactation suppression after full-term deliveries. 
Recently, two randomized controlled trial by Henkel et al found that cabergoline is 
effective in reducing breast symptoms in those undergoing spontaneous and induced abortion 
between 14 and 28 weeks.10,11 Among 69 participants, significantly fewer participants receiving 
cabergoline reported any breast symptoms compared with placebo including engorgement, milk 
leakage, tenderness, and the need for pain relief (27.8% vs 97.0%, P<.001), and fewer reported 
significant bother (2.8% vs 33.3%, P=.001) 4 days after their abortion. Subsequently, a 
prospective cohort study identified cabergoline as acceptable and associated with an 
improvement in breast symptoms from 14 to 24 weeks gestation.12 
Despite the success of these studies, the treatment of these breast symptoms earlier than 
14 weeks has not been adequately evaluated in the literature. This study aims to (1) determine 
the frequency of breast symptoms in those undergoing abortion or pregnancy loss between 12-18 

weeks, and (2) assess the efficacy of cabergoline for inhibiting lactation and breast symptoms in 
these patients. For many patients undergoing abortion or pregnancy loss in the early second 
trimester, their interactions with healthcare providers are often distressing. With this study, we 
hope to improve the patient experience with evidence-based methods to ameliorate discomfort. 
 
STUDY OBJECTIVES 
1. To assess the frequency of breast symptoms including engorgement, milk leakage, 
tenderness, and need for pain relief among pregnant people with 12-18 week pregnancies 
undergoing treatment for spontaneous or induced abortions at Maimonides Medical 
Center 
2. To evaluate if cabergoline, given prophylactically post-abortion, decreases the frequency 
or severity of these breast symptoms 
 
HYPOTHESIS  
Patients undergoing treatment of a spontaneous or induced abortion at 12-18 weeks will experience 
frequent breast symptoms including engorgement, milk leakage, tenderness, and need for pain 
relief. Cabergoline will be effective in inhibiting lactation and decreasing the frequency of these 
symptoms. 
 
STUDY DESIGN 
 
Subjects: Patients undergoing termination of pregnancy or pregnancy loss between 12 and 18 
weeks of gestation at Maimonides Medical Center 
 
Eligibility Criteria: 
Inclusion Criteria:  
Pregnant people aged 18 years or older who are between 12 and 18 weeks of gestation undergoing 
abortion or pregnancy loss at Maimonides Medical Center. 
 
Exclusion Criteria:  
Patients with prior mastectomy, those currently breastfeeding, those currently receiving a 
dopamine agonist or antagonist for other indication, or those with a contraindication to 
cabergoline per the package insert, which includes: 
- 
Uncontrolled hypertension or known hypersensitivity to ergot derivatives 
- 
History of cardiac valvular disorders, as suggested by anatomical evidence of 
valvulopathy 
- 
history of pulmonary, pericardial, or retroperitoneal fibrotic disorders 
 
Design:  
 

Our study will include two phases. In the first phase, we will survey pregnant people who have 
abortions between 12-18 weeks to determine the prevalence of breast symptoms. Through these 
surveys, we will understand how common breast engorgement, milk leakage, tenderness, and 
need for pain relief are experienced among this group. We will use the Bristol Breast Symptoms 
Inventory (see Attachment 1), a validated postpartum measure, to have patients rate the severity 
of their symptoms. The scale ranks each of the four domains of breast pain (breast engorgement, 
milk leakage, tenderness, and need for pain relief) on a scale of 1-4, where a lower score 
indicates less or no symptoms, and a higher score indicates more severe symptoms. This survey 
will be administered to all patients who meet eligibility criteria and complete informed consent 
prior to randomization for Phase 2. Based on our sample size calculation (see below), we 
estimate 348 participants will complete this initial survey. Given that Phase 1 and 2 will occur 
simultaneously and that the Phase 1 survey will occur immediately prior to randomization for 
Phase 2, all participants who enroll in Phase 2 will automatically complete Phase 1. 
The second phase of this study will include a double-blinded randomized controlled trial, during 
which pregnant people who have spontaneous or induced abortions between 12 and 18 weeks 
will be randomized to oral cabergoline or placebo 1 hour after abortion. Both participants and 
providers will be blinded to randomization. 
All patients who agree to participate will receive a single dose of either 1mg of cabergoline or a 
placebo directly following their abortion. They will then be asked to complete multiple surveys. 
The first survey will be a pre-intervention survey to assess baseline breast symptoms and will be 
done prior to pregnancy termination and completed in-person via REDCap. Subsequent surveys 
will be administered online on days 2, 3, 4, 7, and 14 following the abortion via REDCap. 
REDCap is a web-based password-protected application on a secure platform behind the 
Maimonides Medical Center firewall. 
Invitations will be sent through email before 9 AM on the appropriate day. A phone call will be 
made to participants between 5:00 pm and 8:00 pm if the survey is not completed that day. If 
participants do not complete the survey on the day requested, their data will not be collected for 
that day. A subsequent email for the following survey will be sent as described above. Following 
completion of the Day 14 survey, a virtual gift card for 31 USD will be sent via Giftogram. A 
subgroup of participants, approximately 20, will be asked to return on days 0, 4, 7, and 14 to test 
serum prolactin levels. These participants will be chosen at random to offer a blood draw. Blood 
draws will not be mandatory to participate in either Phase 1 or 2 of the study. A single tube of 
blood will be drawn, averaging between 6-10mL, one time. 
 
Data Collection Procedures:  
 

Quantitative data will be collected during all parts of the study. Surveys will assess breast 
symptoms such as engorgement, milk leakage, tenderness, and need for pain relief. We will also 
measure serum prolactin levels. 
   
Data Analysis:  
 
Baseline characteristics between the two groups will be compared using X2 and t tests. 
Descriptive statistics will be calculated to assess the baseline rate of breast symptoms in this 
population. For our primary outcome (percentage of patients with breast symptoms 4 days after 
procedure), we will use X2 or Fisher exact testing, as appropriate. Using similar statistical 
testing, we will also compare the two groups on the four domains of breast pain (engorgement, 
milk leakage, tenderness, and need for pain relief). Secondary outcome measures of bother and 
satisfaction are ordinal in nature and their distribution is nonparametric; thus, we will compare 
the medians between groups with Wilcoxon rank sum test. Serum prolactin levels will be 
assumed nonparametric and compared with Wilcoxon rank sum test. 
 
Sample Size:  
We anticipate about 25% of participants will experience breast symptoms following their 
abortion, given that lactogenesis is thought to start at 12 weeks and the reported frequency of 
breast symptoms in the second trimester in the published literature. If our preliminary results 
indicate that less than 25% of participants experience breast symptoms, we will still continue 
with Phase 2 of the study, but acknowledge this as a limitation in our statistical analysis, as there 
still may be benefit to giving cabergoline at this gestational age range even if symptoms are less 
frequent. If this occurs, sub-analysis will be conducted to assess improvement in breast 
symptoms among those who were initially symptomatic. 
Given that much of the literature suggests that cabergoline inhibits lactation and breast 
symptoms, we anticipate that cabergoline will have similar effects on our target population. 
Given a 95% confidence interval and a p<0.05, we will need to recruit 145 individuals per arm to 
see a 30% decrease in symptoms. To account for the possibility of a 20% loss to follow up we 
will recruit 174 individuals per arm. We aim to recruit 348 participants in total. 
 
Expected Outcomes:  
 
We expect that pregnant people with abortions during 2-18 weeks of gestation will experience 
breast symptoms including engorgement, milk leakage, tenderness, and need for pain relief. We 
expect that cabergoline will effectively reduce the frequency of these symptoms. 
Timetable:   

June 2025: Anticipated MRDF funding approval, IRB submission 
November 2025 – November 2027: Data collection 
March 2026 – December 2027: Data analysis 
November 2027 – January 2028: Manuscript preparation and submission, presentation at national 
conferences 
 
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