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Completed

NCT Number: NCT07157930

Prenatal Hormonal Markers and Sleep Characteristics in Young Adults With Joint Hypermobility

Joint hypermobility is a clinical condition characterized by joints having a range of motion beyond their normal limits. Hormonal factors are thought to play a role in the development of joint hypermobility. One of the most significant indicators of prenatal androgen exposure is considered the ratio of the lengths of the second and fourth fingers (2D:4D). The 2D:4D digit ratio refers to the ratio of the lengths of the second finger (2D; index digit ) and the fourth finger (4D; ring digit). Evidence suggests that the 2D:4D ratio is developmentally stable and stabilizes from the second trimester of pregnancy onward.

To our knowledge, intrauterine androgen exposure (2D:4D) has not been examined in populations with joint hypermobility.

Therefore, the planned study aimed to examine the 2D:4D digit ratio in young adults with joint hypermobility and compare it with that of individuals without joint hypermobility.

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Key information

Conditions

Joint Hypermobility Androgen Effect Healty Controls Hormonal Joint Diseases Joint Instability Musculoskeletal Diseases Sleep

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Nigde Omer Halisdemir University

Niğde, Turkey (Türkiye)

About this study

Estrogen affects collagen metabolism and connective tissue structure, which can lead to increased ligament laxity at high levels. Increased estrogen and progesterone during pregnancy cause significant loosening of connective tissue, which can contribute to temporary joint hypermobility. Physiological conditions such as pregnancy and menopause can cause hormonal changes, increasing the risk of joint hypermobility through fluid retention and connective tissue changes.

Testosterone, on the other hand, is a hormone that strengthens muscle mass and tendon structure, while at low levels it can cause connective tissue to remain looser. Therefore, the combination of high estrogen and relatively low testosterone, particularly in women of reproductive age, may contribute to the higher prevalence of hypermobility.

Therefore, the aim of the planned study was to examine the 2D:4D digit ratio in young adults with joint hypermobility and compare this ratio with individuals without joint hypermobility.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Individuals aged 18-35
  • Individuals who scored 5 out of 9 or higher on the Beighton score
  • Control group: Those with a Beighton score of ≤ 4

Exclusion criteria

  • Individuals with any pathology related to the musculoskeletal system
  • Individuals diagnosed with metabolic, neurological, or genetic diseases (tissue diseases such as Ehlers-Danlos syndrome and Marfan syndrome)
  • Those with a history of surgery within the last 6 months
  • Those who are pregnant or breastfeeding

Treatment and study plan

The Beighton Scoring system

Behavioral

The Beighton Scoring System is widely used to distinguish individuals with generalized joint hypermobility from those without. The Beighton Scoring System consists of: • Passive dorsiflexion of the fifth metacarpophalangeal joint • Passive hyperextension of the elbow • Passive hyperextension of the knee joint • Passive placement of the thumb on the flexor side of the forearm • Forward flexion of the trunk In adults up to 50 years of age, a score of ≥5 out of 9 indicates joint hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for joint hypermobility.

2D:4D Digit Ratio

Behavioral

The lengths of the second (2D) and fourth (4D) digits will be measured separately on both hands. Measurements will be taken with the participants' hands placed on a flat surface with the palms facing upward. Digit length will be defined as the distance from the midpoint of the proximal crease at the base of the finger to the distal tip of the finger. A digital caliper with a precision of 0.01 mm will be used, and two separate measurements will be obtained for each finger, with the mean value recorded. Based on these measurements, the 2D:4D digit ratio will be calculated for each hand by dividing the length of the second digit by that of the fourth digit. To enhance reliability, assessments will be performed independently by two different researchers, and inter-rater agreement will be evaluated.

Primary outcomes

  1. Beighton Scoring System

    Time frame: 1 month

    Individuals will be assessed for joint hypermobility (Beighton Scoring System) by a physical therapist. The Beighton Scoring System is widely used to distinguish individuals with generalized joint hypermobility from those without. The Beighton Scoring System consists of:

    • Passive dorsiflexion of the fifth metacarpophalangeal joint
    • Passive hyperextension of the elbow
    • Passive hyperextension of the knee joint
    • Passive placement of the thumb on the flexor side of the forearm
    • Forward flexion of the trunk In adults up to 50 years of age, a score of ≥5 out of 9 indicates joint hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for joint hypermobility.

  2. 2D:4D Digit Ratio

    Time frame: 1 month

    The lengths of the second (2D) and fourth (4D) digits will be measured separately on both hands. Measurements will be taken with the participants' hands placed on a flat surface with the palms facing upward. Digit length will be defined as the distance from the midpoint of the proximal crease at the base of the finger to the distal tip of the finger. A digital caliper with a precision of 0.01 mm will be used, and two separate measurements will be obtained for each finger, with the mean value recorded. Based on these measurements, the 2D:4D digit ratio will be calculated for each hand by dividing the length of the second digit by that of the fourth digit. To enhance reliability, assessments will be performed independently by two different researchers, and inter-rater agreement will be evaluated.

Sponsors and collaborators

Lead sponsor

Nigde Omer Halisdemir University

Other

Registry information

Official study title

Relationship Between Prenatal Hormonal Markers in Young Adults With Joint Hypermobility: The Role of the 2D:4D Digit Ratio

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Sep 5, 2025
Registry last updated
Dec 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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