diff --git a/src/interfaces/ecpg/ecpglib/misc.c b/src/interfaces/ecpg/ecpglib/misc.c
index 2b78caeaf5..58fff10697 100644
--- a/src/interfaces/ecpg/ecpglib/misc.c
+++ b/src/interfaces/ecpg/ecpglib/misc.c
@@ -407,17 +407,38 @@ ECPGis_noind_null(enum ECPGttype type, const void *ptr)
 
 #ifdef WIN32
 
-void
-win32_pthread_mutex(volatile pthread_mutex_t *mutex)
+int
+pthread_mutex_init(pthread_mutex_t *mp, void *attr)
 {
-	if (mutex->handle == NULL)
+	mp->initstate = 0;
+	return 0;
+}
+
+int
+pthread_mutex_lock(pthread_mutex_t *mp)
+{
+	/* Initialize the csection if not already done */
+	if (mp->initstate != 1)
 	{
-		while (InterlockedExchange((LONG *) &mutex->initlock, 1) == 1)
-			Sleep(0);
-		if (mutex->handle == NULL)
-			mutex->handle = CreateMutex(NULL, FALSE, NULL);
-		InterlockedExchange((LONG *) &mutex->initlock, 0);
+		LONG		istate;
+
+		while ((istate = InterlockedExchange(&mp->initstate, 2)) == 2)
+			Sleep(0);			/* wait, another thread is doing this */
+		if (istate != 1)
+			InitializeCriticalSection(&mp->csection);
+		InterlockedExchange(&mp->initstate, 1);
 	}
+	EnterCriticalSection(&mp->csection);
+	return 0;
+}
+
+int
+pthread_mutex_unlock(pthread_mutex_t *mp)
+{
+	if (mp->initstate != 1)
+		return EINVAL;
+	LeaveCriticalSection(&mp->csection);
+	return 0;
 }
 
 static pthread_mutex_t win32_pthread_once_lock = PTHREAD_MUTEX_INITIALIZER;
diff --git a/src/interfaces/ecpg/include/ecpg-pthread-win32.h b/src/interfaces/ecpg/include/ecpg-pthread-win32.h
index 8252a17809..7b6ba46b34 100644
--- a/src/interfaces/ecpg/include/ecpg-pthread-win32.h
+++ b/src/interfaces/ecpg/include/ecpg-pthread-win32.h
@@ -12,29 +12,23 @@
 
 typedef struct pthread_mutex_t
 {
-	HANDLE		handle;
-	LONG		initlock;
+	/* initstate = 0: not initialized; 1: init done; 2: init in progress */
+	LONG		initstate;
+	CRITICAL_SECTION csection;
 } pthread_mutex_t;
 
 typedef DWORD pthread_key_t;
 typedef bool pthread_once_t;
 
-#define PTHREAD_MUTEX_INITIALIZER	{ NULL, 0 }
+#define PTHREAD_MUTEX_INITIALIZER	{ 0 }
 #define PTHREAD_ONCE_INIT			false
 
-void		win32_pthread_mutex(volatile pthread_mutex_t *mutex);
+int			pthread_mutex_init(pthread_mutex_t *, void *attr);
+int			pthread_mutex_lock(pthread_mutex_t *);
+int			pthread_mutex_unlock(pthread_mutex_t *);
+
 void		win32_pthread_once(volatile pthread_once_t *once, void (*fn) (void));
 
-#define pthread_mutex_lock(mutex) \
-	do { \
-		if ((mutex)->handle == NULL) \
-			win32_pthread_mutex((mutex)); \
-		WaitForSingleObject((mutex)->handle, INFINITE); \
-	} while(0)
-
-#define pthread_mutex_unlock(mutex) \
-	ReleaseMutex((mutex)->handle)
-
 #define pthread_getspecific(key) \
 	TlsGetValue((key))
 
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 64c0b628b3..d4e10a0c4f 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -7426,24 +7426,8 @@ error:
 static void
 default_threadlock(int acquire)
 {
-#ifndef WIN32
 	static pthread_mutex_t singlethread_lock = PTHREAD_MUTEX_INITIALIZER;
-#else
-	static pthread_mutex_t singlethread_lock = NULL;
-	static long mutex_initlock = 0;
 
-	if (singlethread_lock == NULL)
-	{
-		while (InterlockedExchange(&mutex_initlock, 1) == 1)
-			 /* loop, another thread own the lock */ ;
-		if (singlethread_lock == NULL)
-		{
-			if (pthread_mutex_init(&singlethread_lock, NULL))
-				Assert(false);
-		}
-		InterlockedExchange(&mutex_initlock, 0);
-	}
-#endif
 	if (acquire)
 	{
 		if (pthread_mutex_lock(&singlethread_lock))
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index 6bc216956d..8110882262 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -91,12 +91,7 @@ static bool ssl_lib_initialized = false;
 
 static long crypto_open_connections = 0;
 
-#ifndef WIN32
 static pthread_mutex_t ssl_config_mutex = PTHREAD_MUTEX_INITIALIZER;
-#else
-static pthread_mutex_t ssl_config_mutex = NULL;
-static long win32_ssl_create_mutex = 0;
-#endif
 
 static PQsslKeyPassHook_OpenSSL_type PQsslKeyPassHook = NULL;
 static int	ssl_protocol_version_to_openssl(const char *protocol);
@@ -773,20 +768,6 @@ pq_lockingcallback(int mode, int n, const char *file, int line)
 int
 pgtls_init(PGconn *conn, bool do_ssl, bool do_crypto)
 {
-#ifdef WIN32
-	/* Also see similar code in fe-connect.c, default_threadlock() */
-	if (ssl_config_mutex == NULL)
-	{
-		while (InterlockedExchange(&win32_ssl_create_mutex, 1) == 1)
-			 /* loop, another thread own the lock */ ;
-		if (ssl_config_mutex == NULL)
-		{
-			if (pthread_mutex_init(&ssl_config_mutex, NULL))
-				return -1;
-		}
-		InterlockedExchange(&win32_ssl_create_mutex, 0);
-	}
-#endif
 	if (pthread_mutex_lock(&ssl_config_mutex))
 		return -1;
 
@@ -874,7 +855,6 @@ static void
 destroy_ssl_system(void)
 {
 #if defined(HAVE_CRYPTO_LOCK)
-	/* Mutex is created in pgtls_init() */
 	if (pthread_mutex_lock(&ssl_config_mutex))
 		return;
 
diff --git a/src/interfaces/libpq/pthread-win32.c b/src/interfaces/libpq/pthread-win32.c
index e607bee89a..b40872898d 100644
--- a/src/interfaces/libpq/pthread-win32.c
+++ b/src/interfaces/libpq/pthread-win32.c
@@ -34,27 +34,33 @@ pthread_getspecific(pthread_key_t key)
 int
 pthread_mutex_init(pthread_mutex_t *mp, void *attr)
 {
-	*mp = (CRITICAL_SECTION *) malloc(sizeof(CRITICAL_SECTION));
-	if (!*mp)
-		return 1;
-	InitializeCriticalSection(*mp);
+	mp->initstate = 0;
 	return 0;
 }
 
 int
 pthread_mutex_lock(pthread_mutex_t *mp)
 {
-	if (!*mp)
-		return 1;
-	EnterCriticalSection(*mp);
+	/* Initialize the csection if not already done */
+	if (mp->initstate != 1)
+	{
+		LONG		istate;
+
+		while ((istate = InterlockedExchange(&mp->initstate, 2)) == 2)
+			Sleep(0);			/* wait, another thread is doing this */
+		if (istate != 1)
+			InitializeCriticalSection(&mp->csection);
+		InterlockedExchange(&mp->initstate, 1);
+	}
+	EnterCriticalSection(&mp->csection);
 	return 0;
 }
 
 int
 pthread_mutex_unlock(pthread_mutex_t *mp)
 {
-	if (!*mp)
-		return 1;
-	LeaveCriticalSection(*mp);
+	if (mp->initstate != 1)
+		return EINVAL;
+	LeaveCriticalSection(&mp->csection);
 	return 0;
 }
diff --git a/src/port/pthread-win32.h b/src/port/pthread-win32.h
index 97ccc17a12..5f33269057 100644
--- a/src/port/pthread-win32.h
+++ b/src/port/pthread-win32.h
@@ -5,7 +5,16 @@
 #define __PTHREAD_H
 
 typedef ULONG pthread_key_t;
-typedef CRITICAL_SECTION *pthread_mutex_t;
+
+typedef struct pthread_mutex_t
+{
+	/* initstate = 0: not initialized; 1: init done; 2: init in progress */
+	LONG		initstate;
+	CRITICAL_SECTION csection;
+} pthread_mutex_t;
+
+#define PTHREAD_MUTEX_INITIALIZER	{ 0 }
+
 typedef int pthread_once_t;
 
 DWORD		pthread_self(void);