Threatened AbortionNCT07357922
Serum Progesterone and Threatened Abortion During Lactation
An observational study of Threatened Abortion, run by Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization.
Trial summary
This study aims to evaluate the effect of first-trimester maternal serum progesterone levels on threatened abortion in women who conceive during the lactation period. Serum progesterone concentrations will be measured in lactating pregnant women during the first trimester, and their association with the etiology of… Read more about this study
- Who is it for?
- Ages 18 to 50 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Threatened Abortion
- How many people
- 150 participants
- Where
- No sites listed yet
- Study dates
- 1 Jan 2026to 1 Jan 2028
- How long will I take part?
- 4 Months
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- Women only
- Healthy volunteers accepted
- Adult
Study population: The study population consists of lactating pregnant women aged 18 to 50 years who present for routine antenatal care during the first trimester of pregnancy at the participating obstetrics and gynecology clinics. Eligible participants include women who conceived while breastfeeding and have available first-trimester serum progesterone measurements. Participants will be prospectively followed to evaluate the occurrence of threatened abortion and early pregnancy outcomes.
Who may be able to join
- Female participants aged 18 to 50 years.
- Pregnant women who conceived during the lactation period.
- Singleton pregnancy.
- First-trimester pregnancy.
- Availability of first-trimester serum progesterone measurement obtained as part of routine antenatal care.
- Ongoing follow-up at the participating hospitals.
Who cannot join
- Age under 18 years or over 50 years.
- Multiple pregnancies.
- Known chronic medical diseases.
- Use of progesterone supplementation before serum progesterone measurement.
- Missing or incomplete clinical or laboratory data.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Association Between Maternal Serum Progesterone Levels and Threatened Abortion in Lactating Pregnant Women
This study aims to evaluate the effect of first-trimester maternal serum progesterone levels on threatened abortion in women who conceive during the lactation period. Serum progesterone concentrations will be measured in lactating pregnant women during the first trimester, and their association with the etiology of threatened abortion will be analyzed.
Threatened abortion is defined as vaginal bleeding occurring in the first trimester of pregnancy and represents a risk for early pregnancy loss. Previous studies have shown that serum progesterone levels may be lower in cases of threatened abortion compared to healthy pregnancies and play an essential role in predicting miscarriage risk. Serum progesterone is therefore considered a useful biomarker for assessing pregnancy viability and prognosis.
During lactation, progesterone levels may vary depending on breastfeeding duration and maternal hormonal status, and generally remain low, similar to follicular-phase levels in non-pregnant women. However, normal reference values during lactation are not well established. This study aims to contribute new data to the limited literature on the relationship between lactation, serum progesterone levels, and threatened abortion, and to provide insights that may help improve early pregnancy loss prevention strategies.
Read the detailed description
This study is designed to investigate the relationship between maternal serum progesterone levels and threatened abortion in women who conceive during the lactation period. The primary objective is to evaluate first-trimester serum progesterone concentrations in lactating pregnant women and to assess their role in the etiology and clinical course of threatened abortion.
Threatened abortion is characterized by vaginal bleeding during the first trimester of pregnancy and is associated with an increased risk of early pregnancy loss. Progesterone plays a critical role in the maintenance of early pregnancy by supporting endometrial receptivity, suppressing uterine contractility, and modulating maternal immune tolerance. Previous studies have demonstrated that serum progesterone levels tend to be lower in pregnancies complicated by threatened abortion compared to uncomplicated pregnancies, and that reduced progesterone concentrations may be predictive of subsequent miscarriage.
Lactation is associated with distinct hormonal changes, primarily mediated by elevated prolactin levels, which suppress ovulation and result in progesterone levels comparable to those observed during the follicular phase of the menstrual cycle. Although progesterone levels increase following conception, the hormonal milieu during lactation may influence progesterone production and regulation in early pregnancy. However, normal reference ranges for serum progesterone levels in lactating pregnant women have not been clearly established, and data regarding their association with threatened abortion remain limited.
In this study, pregnant women who conceive during the lactation period will be enrolled. Maternal serum progesterone levels will be measured during the first trimester, and participants will be evaluated for the presence or absence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy. Clinical, obstetric, and demographic data will be recorded to allow assessment of potential confounding factors.
By examining the relationship between serum progesterone levels and threatened abortion in lactating pregnancies, this study aims to provide new insights into the hormonal mechanisms underlying early pregnancy complications. The findings may contribute to improved risk stratification, early diagnosis, and management strategies for threatened abortion in this specific population. Additionally, the study seeks to expand the limited body of literature on lactation-associated hormonal changes during early pregnancy and their clinical implications.
- Conditions
- Threatened Abortion
- Keywords
- Serum Progesterone Levels, Threatened Abortion, Lactation During Pregnancy
- Medical subject headings
- Abortion, Threatened
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Lactating Pregnant Women (First Trimester) | Pregnant women who conceived during the lactation period and are in the first trimester of pregnancy. Maternal serum progesterone levels will be measured at enrollment. Participants will be prospectively followed to evaluate the occurrence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy. This is a prospective observational cohort study, and no interventions are assigned. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of Threatened Abortion in Lactating Pregnant Women
The incidence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy, assessed by clinical evaluation and ultrasonographic confirmation.
Measured: From enrollment in the first trimester until 14 weeks of gestation
Secondary outcomes (3)
First-Trimester Serum Progesterone Levels
Maternal serum progesterone levels measured during the first trimester of pregnancy will be recorded and compared between women with and without threatened abortion.
Measured: At enrollment during the first trimester of pregnancy
Early Pregnancy Loss
The occurrence of pregnancy loss before 14 weeks of gestation will be recorded and evaluated in relation to first-trimester serum progesterone levels.
Measured: Up to 14 weeks of gestation
Serum Progesterone Cut-off Value for Predicting Threatened Abortion
The optimal first-trimester serum progesterone cut-off value for predicting threatened abortion in lactating pregnant women will be determined using receiver operating characteristic (ROC) curve analysis.
Measured: During the first trimester of pregnancy
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Jan 2026
- Study start1 Jan 2026 (estimated)
- Primary completion31 Dec 2027 (estimated)
- Study completion1 Jan 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Threatened AbortionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 150 participants (estimated)
- Target duration
- 4 Months
Sponsor and investigators
- Lead sponsor
- Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Burak Deniz Aydoğdu, Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization
- Investigators
- Burak D. Aydoğdu, M.D., Principal investigator, Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07357922
- Sponsor's protocol ID
- 2025/517
- Status last verified
- Jan 2026
- First submitted
- 14 Jan 2026
- Last updated
- 26 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Although data would be de-identified before any potential sharing, individual participant data will not be shared because the original ethics committee approval and informed consent do not permit data sharing beyond the study team. In addition, the dataset contains detailed clinical and laboratory variables that could carry a risk of re-identification. Any future data sharing would require additional ethics committee approval and updated participant consent. Study results will be disseminated in aggregated and anonymized form through scientific publications.
Publications
Sammut L, Bezzina P, Gibbs V, Muscat-Baron Y, Agius-Camenzuli A, Calleja-Agius J. Predicting first-trimester pregnancy outcome in threatened miscarriage: A comparison of a multivariate logistic regression and machine learning models. Radiography (Lond). 2025 Oct;31(6):103159. doi: 10.1016/j.radi.2025.103159. Epub 2025 Sep 4.
PubMed 40912049Jiang TT, Zhang DY, Liu ZY, Lu ZS, Yan LM, Sun S, Xie JA, Zhu M, Zhang ZH, Wan YH, Wang H, Hao JH, Zhang C. Association of co-exposure to EDCs in early pregnancy with threatened abortion: The mediation effect of progesterone. Environ Int. 2026 Jan;207:110001. doi: 10.1016/j.envint.2025.110001. Epub 2025 Dec 11.
PubMed 41391232
Study at a glance
From the registry record, last updated by the sponsor on 26 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Association Between Maternal Serum Progesterone Levels and Threatened Abortion in Lactating Pregnant Women
- ClinicalTrials.gov ID
- NCT07357922
- Acronym / sponsor ID
- 2025/517
- Conditions
- Threatened Abortion
- Keywords
- Serum Progesterone Levels, Threatened Abortion, Lactation During Pregnancy
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Prof. Dr. Cemil Tascıoglu Education and Research Hospital OrganizationUniversity, hospital or other
- Study start
- 1 Jan 2026 (estimated)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 1 Jan 2028 (estimated)
- First posted
- 22 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to evaluate the effect of first-trimester maternal serum progesterone levels on threatened abortion in women who conceive during the lactation period. Serum progesterone concentrations will be measured in lactating pregnant women during the first trimester, and their association with the etiology of threatened abortion will be analyzed.
Threatened abortion is defined as vaginal bleeding occurring in the first trimester of pregnancy and represents a risk for early pregnancy loss. Previous studies have shown that serum progesterone levels may be lower in cases of threatened abortion compared to healthy pregnancies and play an essential role in predicting miscarriage risk. Serum progesterone is therefore considered a useful biomarker for assessing pregnancy viability and prognosis.
During lactation, progesterone levels may vary depending on breastfeeding duration and maternal hormonal status, and generally remain low, similar to follicular-phase levels in non-pregnant women. However, normal reference values during lactation are not well established. This study aims to contribute new data to the limited literature on the relationship between lactation, serum progesterone levels, and threatened abortion, and to provide insights that may help improve early pregnancy loss prevention strategies.
Detailed description
This study is designed to investigate the relationship between maternal serum progesterone levels and threatened abortion in women who conceive during the lactation period. The primary objective is to evaluate first-trimester serum progesterone concentrations in lactating pregnant women and to assess their role in the etiology and clinical course of threatened abortion.
Threatened abortion is characterized by vaginal bleeding during the first trimester of pregnancy and is associated with an increased risk of early pregnancy loss. Progesterone plays a critical role in the maintenance of early pregnancy by supporting endometrial receptivity, suppressing uterine contractility, and modulating maternal immune tolerance. Previous studies have demonstrated that serum progesterone levels tend to be lower in pregnancies complicated by threatened abortion compared to uncomplicated pregnancies, and that reduced progesterone concentrations may be predictive of subsequent miscarriage.
Lactation is associated with distinct hormonal changes, primarily mediated by elevated prolactin levels, which suppress ovulation and result in progesterone levels comparable to those observed during the follicular phase of the menstrual cycle. Although progesterone levels increase following conception, the hormonal milieu during lactation may influence progesterone production and regulation in early pregnancy. However, normal reference ranges for serum progesterone levels in lactating pregnant women have not been clearly established, and data regarding their association with threatened abortion remain limited.
In this study, pregnant women who conceive during the lactation period will be enrolled. Maternal serum progesterone levels will be measured during the first trimester, and participants will be evaluated for the presence or absence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy. Clinical, obstetric, and demographic data will be recorded to allow assessment of potential confounding factors.
By examining the relationship between serum progesterone levels and threatened abortion in lactating pregnancies, this study aims to provide new insights into the hormonal mechanisms underlying early pregnancy complications. The findings may contribute to improved risk stratification, early diagnosis, and management strategies for threatened abortion in this specific population. Additionally, the study seeks to expand the limited body of literature on lactation-associated hormonal changes during early pregnancy and their clinical implications.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 4 Months
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Lactating Pregnant Women (First Trimester) | – | –Pregnant women who conceived during the lactation period and are in the first trimester of pregnancy. Maternal serum progesterone levels will be measured at enrollment. Participants will be prospectively followed to evaluate the occurrence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy. This is a prospective observational cohort study, and no interventions are assigned. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- The study population consists of lactating pregnant women aged 18 to 50 years who present for routine antenatal care during the first trimester of pregnancy at the participating obstetrics and gynecology clinics. Eligible participants include women who conceived while breastfeeding and have available first-trimester serum progesterone measurements. Participants will be prospectively followed to evaluate the occurrence of threatened abortion and early pregnancy outcomes.
Key inclusion criteria (6 listed)
- Female participants aged 18 to 50 years.
- Pregnant women who conceived during the lactation period.
- Singleton pregnancy.
- First-trimester pregnancy.
- Availability of first-trimester serum progesterone measurement obtained as part of routine antenatal care.
Key exclusion criteria (5 listed)
- Age under 18 years or over 50 years.
- Multiple pregnancies.
- Known chronic medical diseases.
- Use of progesterone supplementation before serum progesterone measurement.
- Missing or incomplete clinical or laboratory data.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Incidence of Threatened Abortion in Lactating Pregnant Women
Time frame: From enrollment in the first trimester until 14 weeks of gestation
The incidence of threatened abortion, defined as first-trimester vaginal bleeding with a viable intrauterine pregnancy, assessed by clinical evaluation and ultrasonographic confirmation.
3 secondary outcomes
First-Trimester Serum Progesterone Levels
Time frame: At enrollment during the first trimester of pregnancy
Early Pregnancy Loss
Time frame: Up to 14 weeks of gestation
Serum Progesterone Cut-off Value for Predicting Threatened Abortion
Time frame: During the first trimester of pregnancy
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Jan 2026.
- Background: PubMed 40912049Sammut L, Bezzina P, Gibbs V, Muscat-Baron Y, Agius-Camenzuli A, Calleja-Agius J. Predicting first-trimester pregnancy outcome in threatened miscarriage: A comparison of a multivariate logistic regression and machine learning models. Radiography (Lond). 2025 Oct;31(6):103159. doi: 10.1016/j.radi.2025.103159. Epub 2025 Sep 4.
- Background: PubMed 41391232Jiang TT, Zhang DY, Liu ZY, Lu ZS, Yan LM, Sun S, Xie JA, Zhu M, Zhang ZH, Wan YH, Wang H, Hao JH, Zhang C. Association of co-exposure to EDCs in early pregnancy with threatened abortion: The mediation effect of progesterone. Environ Int. 2026 Jan;207:110001. doi: 10.1016/j.envint.2025.110001. Epub 2025 Dec 11.
- Individual participant dataSharing planned: No. Although data would be de-identified before any potential sharing, individual participant data will not be shared because the original ethics committee approval and informed consent do not permit data sharing beyond the study team. In addition, the dataset contains detailed clinical and laboratory variables that could carry a risk of re-identification. Any future data sharing would require additional ethics committee approval and updated participant consent. Study results will be disseminated in aggregated and anonymized form through scientific publications.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Burak D. Aydoğdu, M.D. principal investigator
Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization
Questions about this trial
What is this clinical trial studying?
An observational study of Threatened Abortion, run by Prof. Dr. Cemil Tascıoglu Education and Research Hospital Organization.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 26 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Burak D Aydoğdu, M.D. (+90 539 618 2228, burakd.1992@hotmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of Threatened Abortion in Lactating Pregnant Women (time frame: From enrollment in the first trimester until 14 weeks of gestation). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07357922, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Jan 2026.