Sleep, Oxytocin and Reward Processing in Women in the Postpartum Phase

The Role of Sleep, Oxytocin and Reward Processing in Women in the Postpartum Phase

During and after pregnancy, a woman's body and brain undergo significant changes that help her adapt to caregiving and emotional needs. However, this period also makes women more susceptible to emotional disorders, such as peripartum depression (PPD), which affects about 10-15% of new mothers. PPD can negatively impact both the mother and her baby, disrupting mood, motivation, and mothering abilities. Hormonal changes and poor sleep are some of the risk factors that might worsen these depressive symptoms.

Traditionally, sleep studies on PPD have relied on questionnaires and short-term sleep assessments. With the advent of smartwatches and digital devices, we can now monitor sleep in a home environment over longer periods. Oxytocin, a hormone crucial for childbirth, breastfeeding, and bonding with the baby, is thought to play a role in PPD. Studies suggest that higher levels of oxytocin might be linked to lower levels of postpartum depression, though findings are not always consistent. Oxytocin also affects sleep and is connected to brain areas that regulate reward and motivation.

This study aims to explore the relationship between sleep, oxytocin, and reward processing in new mothers. The investigators will include women with varying levels of depressive symptoms and use home-based sleep assessments to gather data. Our goal is to better understand how these factors interact in the postpartum period and how they might influence a mother's mental health and caregiving abilities.

The investigators expect that oxytocin levels are reduced in women with higher depressive symptoms and that these reductions are associated with sleep impairments, breastfeeding and altered reward processing.

Study Overview

• Status: Not yet recruiting
• Conditions: Postpartum Depression

Detailed Description

The study will be conducted at Uppsala University. Data will be mainly collected at the participants' home. The investigators plan to include 100 women in the postpartum phase in total, including women with different depressive scores according to the Edinburgh Postnatal Depression Scale (EPDS). Ideally, the investigators aim to include 50 women with depressive symptoms (EPDS ≥12) and 50 women without depressive symptoms (EPDS score ≤6). However, depending on the number of available participants and recruitment efforts the investigators will possibly include all interested women in the postpartum phase to increase the feasibility of the study and use a continuous categorization of the depressive (EPDS) scores.

The participants will be asked to fill out (online) questionnaires. The investigators will assess their demographic data and socioeconomic status as well depressive symptoms (Montgommery Asberg Depression Scale (MADRS); Edinburgh Postnatal Depression Score (EPDS)) and sleep/chronotype (morningness-eveningness questionnaire (MEQ); Pittsburg Sleep Quality Index (PSQI); Ford Insomnia Response to Stress Test (FIRST); Insomnia severity index (ISI); Epworth sleepiness scale (ESS); Fatigue Severity Scale (FSS)). Additionally, the investigators will include sleep questionnaires which are specific for the postpartum phase (Postpartum Sleep Quality Scale (PSQS)) and ask the mothers to rate the infants sleep using the Brief Infant Sleep Questionnaire (BISQ-R). Participants will be asked to fill out questionnaire regarding their breastfeeding behavior (Breastfeeding Self-Efficacy Scale Short Form (BSES-SF); Baby Eating Behavior Questionnaire (BEBQ)), bonding (Postpartum Bonding Questionnaire (PBQ); Swedish mother to infant bonding scale (S-MIBS)) and reward processing (indecisiveness scale IS, action regulation ARES).

Participants will take part in an online behavioral task ("Effort Allocation Task (EAT)") that assesses reward processing, in particular motivation for primary rewards (i.e. food) and secondary rewards (i.e. money) (approximately 20 minutes).

The experimenter will explain all the procedures for the at-home assessment and participants will be given the devices accordingly. For the at-home measurement of sleep, participants will receive tracking devices (Fitbit Inspire; Withings sleep analyser) which they should use for one week (7 days) to assess sleep multimodally. The Fitbit will also assess daily physiological measures i.e., physical activity during the day and heart rate. Additionally, subjective sleep, breastfeeding and the current mood will be assessed at several timepoints throughout the week using standardized diaries and questionnaires.

Furthermore, the participants will receive saliva sample kits to use at different timepoints throughout the measurement period to assess endogenous oxytocin levels. If participants are breastfeeding, the investigators will additionally ask them to take saliva samples before and after a breastfeeding period to assess changes in salivary oxytocin associated with breastfeeding.

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Christian Benedict, PhD; Phone Number: +46 18 471 43 30; Email: christian.benedict@farmbio.uu.se
• Study Contact Backup: Name: Nina Goll, M. Sc.; Phone Number: +49170 29 88918; Email: nina.goll@uni-tuebingen.de

Study Locations

• Sweden
  • Uppsala, Sweden, 751 24
    • University of Uppsala
    • Contact: Christian Benedict, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Research participants will be recruited in the area of Uppsala, Sweden.

Description

Inclusion Criteria:

• Age: 18-40
• Biological sex/gender: female
• Swedish/English fluency
• Postpartum phase: 6 weeks to 1 year

Exclusion Criteria:

• Age < 18
• Neonatal complications

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
objective sleep	Objective sleep measures assessed with tracking devices (Fitbit Inspire; Withings sleep analyser) e.g., total time spent in bed, wake time, wake frequency, sleep stages duration.	7 consecutive nights
subjective sleep	Subjective sleep assessed by a daily sleep diary.	7 consecutive days
oxytocin levels	Oxytocin levels assessed with saliva kits.	7 consecutive days
breastfeeding	Assessment of breastfeeding behavior (onset, frequency and duration) with breastfeeding diaries.	7 consecutive days
bonding	Bonding of mother and child assessed with questionnaires.	7 consecutive days
reward processing/motivation	Assessment of effort-based motivation using the effort allocation task.	7 consecutive days

Collaborators and Investigators

• Sponsor: International Research Training Group 2804
• Collaborators: Uppsala University; Uppsala University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: November 22, 2024
• First Submitted That Met QC Criteria: November 27, 2024
• First Posted (Estimated): December 2, 2024

Study Record Updates

• Last Update Posted (Estimated): December 2, 2024
• Last Update Submitted That Met QC Criteria: November 27, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: sleep; oxytocin; motivation; postpartum depression; reward processing; sleep assessment; peripartum depression
• Additional Relevant MeSH Terms: Urogenital Diseases; Mental Disorders; Female Urogenital Diseases and Pregnancy Complications; Pregnancy Complications; Behavioral Symptoms; Mood Disorders; Puerperal Disorders; Depressive Disorder; Depression; Depression, Postpartum
• Other Study ID Numbers: IRTG_P06_2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No